EDIT (the whole question, it was too unclear)
I want to use OpenSSL.NET
The OpenSSL.NET install instructions page: INSTALL
Make sure you have libeay32.dll and ssleay32.dll in the current working
directory of your application or in your PATH. DONE
In your .NET project, add a reference to the ManagedOpenSsl.dll assembly. DONE
I have put libeay32.dll and ssleay32.dll in both my bin/Debug and bin/Release directories. I have also put them in system32.
Here is my FULL code:
using System;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
try
{
OpenSSL.Crypto.RSA rsa = new OpenSSL.Crypto.RSA();
}
catch (Exception e)
{
Console.WriteLine(e.InnerException.Message);
}
Console.Read();
}
}
}
I get the following error:
Unable to load DLL 'libeay32' http://localhostr.com/files/a719c5/Error.gif
(Unable to load DLL 'libeay32')
Here is the Process Monitor log (upon request):
alt text http://localhostr.com/files/726a46/ProcMon.gif
What am I doing wrong? Why isn't the DLL found?
Try the latest version of OpenSSL.NET (0.4.1) which should now include prebuilt libeay32.dll and ssleay32.dll binaries that link to the CRT statically. Alternatively, you can build these libraries yourself or use an 'official' build from openssl.org.
Without looking at your code exactly, I get that error when I:
do not have the dlls in the path of the executable (not where your sln resides, but where the .exe is made, typically in bin/debug or bin/x86/debug or whatever).
do not have the proper signature of the calling function (ie, I left out an integer parameter, the return types don't match, etc).
am not marshalling the types properly (ie, BOOL is marshalled as a bool, while bool is marshalled as a unsigned single byte integer, etc)-- while this last one may not cause the exception, it can cause decidedly funky behavior.
am on a 64 bit platform and am calling a 32 bit dll. The pointer sizes will be all different, and the dll will probably just crash and cause that exception.
EDIT: When all else fails, try dependency walker, because it sounds like your dlls are calling other dlls that aren't in your path or in the directory of the executable.
For anyone else out there still experiencing this issue (and have verified that the necessary prerequisites exist in their correct locations:
Check the OpenSSL.NET installation documentation and ensure its prerequisites are installed. In my case, a user was missing the Microsoft Visual C++ 2010 Redistributable Package (x86) dependency which is called out in the OpenSSL.NET documentation.
Your problem is related with this question:
DllNotFoundException, but DLL is there
Verify if all depencencies are in same folder of your application or are registred.
Try using probing. You need to create an XML config file named as the application's executable complete name (or named as the assembly that requieres your non-managed dll) with a .config extension. E.g. if your applications is name myapp.exe, the config file will be named myapp.exe.config
The config file must be located in the same directory as the executable / assembly .
The config file is a simple xml file:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<runtime>
<assemblyuBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<probing privatePath="PATH" />
</assemblyuBinding>
</runtime>
</configuration>
Now the application will search in PATH when loading the assemblies. PATH is relative to the config /assembly file.
Not sure if it will work for non-managed dlls, but is worth the try.
The .NET way of doing this is to install your assembly in the global assembly cache.
Each computer where the common
language runtime is installed has a
machine-wide code cache called the
global assembly cache. The global
assembly cache stores assemblies
specifically designated to be shared
by several applications on the
computer.
As a last resort, if nothing else works:
It may be useful to know where the application (.net or not) is looking for the DLLs. Just use Process Monitor and filter for the file name of the DLL. Then copy it to a location where the application is looking for it.
You're probably missing the VC++ redistributables. I'm assuming OpenSSL.NET is x86 only, so you can grab the VS2008 version x86 redistributable if they're release builds.
Otherwise, if they're debug builds (you'll see Microsoft.VC90.DebugCRT in EventViewer or the sxstrace logs) then you'll need to either:
Rebuild them as release
Install or copy the debug redistributables from another machine
Install Visual C++ into Visual Studio (or, probably, Visual C++ Express)
I found a solution.
Unfortunately the VS2008 C++ Redistributable package didn't work - I had to install the SP1 version AND VC++2008. The author said in a comment on its website that it was a mistake on its side, and not mine. He is currently recompiling the DLLs to be statically linked. Thank you to all of those who helped me :)
Try changing the Platform target for your project to x86 instead of "any cpu".
In my case, when we develop a web site with open ssl on x64 win 2008 platforms, we must check with application pool : allow 32 applications : true
Create New Folder Named x86 in your application path and then put libeay32.dll,ssleay32.dll in x86 folder.
Related
I have a dll library with unmanaged C++ API code I need to use in my .NET 4.0 application. But every method I try to load my dll I get an error:
Unable to load DLL 'MyOwn.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
I have read and tried several solutions I have found on the internet. Nothing works..
I have tried using following methods:
[DllImport("MyOwn.dll", CallingConvention = CallingConvention.Cdecl)]
[return: MarshalAs((UnmanagedType.I4))]
public static extern Int32 MyProIni(string DBname, string DBuser_pass,
string WorkDirectory, ref StringBuilder ErrorMessage);
When I tried following this article and when I run this example (from the downloaded code) it runs without a problem (the dll used is in the bin/debug folder)
I have copied my dll (along with all the files the it depends on into my bin folder).
I also tried this approach but got the same error:
[DllImportAttribute(MyOwnLibDllPath, EntryPoint="TMproIni")]
[return: MarshalAs(UnmanagedType.I4)]
public static extern int MyproIni(string DBname, string DBuser_pass,
string WorkDirectory, ref StringBuilder ErrorMessage);
Any suggestions?
From what I remember on Windows the search order for a dll is:
Current Directory
System folder, C:\windows\system32 or c:\windows\SysWOW64 (for 32-bit process on 64-bit box).
Reading from the Path environment variable
In addition I'd check the dependencies of the DLL, the dependency walker provided with Visual Studio can help you out here, it can also be downloaded for free: http://www.dependencywalker.com
You can use the dumpbin tool to find out the required DLL dependencies:
dumpbin /DEPENDENTS my.dll
This will tell you which DLLs your DLL needs to load. Particularly look out for MSVCR*.dll. I have seen your error code occur when the correct Visual C++ Redistributable is not installed.
You can get the "Visual C++ Redistributable Packages for Visual Studio 2013" from the Microsoft website. It installs c:\windows\system32\MSVCR120.dll
In the file name, 120 = 12.0 = Visual Studio 2013.
Be careful that you have the right Visual Studio version (10.0 = VS 10, 11 = VS 2012, 12.0 = VS 2013...) right architecture (x64 or x86) for your DLL's target platform, and also you need to be careful around debug builds. The debug build of a DLL depends on MSVCR120d.dll which is a debug version of the library, which is installed with Visual Studio but not by the Redistributable Package.
The DLL has to be in the bin folder.
In Visual Studio, I add the dll to my project NOT in References, but "Add existing file". Then set the "Copy to Output Directory" Property for the dll to "Copy if newer".
This is a 'kludge' but you could at least use it to sanity-test:
Try hard-coding the path to the DLL in your code
[DllImport(#"C:\\mycompany\\MyDLL.dll")]
Having said that; in my case running dumpbin /DEPENDENTS as suggested by #anthony-hayward, and copying over 32-bit versions of the DLLs listed there into my working directory solved this problem for me.
The message is just a bit misleading, becuase it isn't "my" dll that can't be loaded - it's the dependencies
Try to enter the full-path of the dll.
If it doesn't work, try to copy the dll into the system32 folder.
"Unable to load DLL 'xxx.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)" means the file CAN be found BUT it's not able to load it. Try to copy the DLL file to the root folder of your application, some DLL libraries need to be available in the root folder of the application in order for it to work. Or check if there are any other depending DLL files required by it.
"Cannot find DLL 'xxx.dll': ..." means the file CANNOT be found. Try to check the path. For example, [DllImport(#"\Libraries\Folder\xxx.dll")]
Ensure that all dependencies of your own dll are present near the dll, or in System32.
Turn on the fusion logging, see this question for lots of advice on how to do that. Debugging mixed-mode apps loading problems can be a right royal pain. The fusion logging can be a big help.
Make sure you set the Build Platform Target to x86 or x64 so that it is compatible with your DLL - which might be compiled for a 32 bit platform.
There is one very funny thing (and has a technical relevance) which might waste your hours so thought of sharing it here -
I created a console application project ConsoleApplication1 and a class library project ClassLibrary1.
All the code which was making the p/invoke was present in ClassLibrary1.dll. So before debugging the application from visual studio I simply copied the C++ unmanaged assembly (myUnmanagedFunctions.dll) into the \bin\debug\ directory of ClassLibrary1 project so that it can be loaded at run-time by the CLR.
I kept getting the
Unable to load DLL
error for hours. Later on I realized that all such unmanaged assemblies which are to be loaded need to be copied into the \bin\debug directory of the start-up project ConsoleApplication1 which is usually a win form, console or web application.
So please be cautious the Current Directory in the accepted answer actually means Current Directory of main executable from where you application process is starting. Looks like an obvious thing but might not be so at times.
Lesson Learnt - Always place the unamanaged dlls in the same directory as the start-up executable to ensure that it can be found.
I had the same problem when I deployed my application to test PC. The problem was development PC had msvcp110d.dll and msvcr110d.dll but not the test PC.
I added "Visual Studio C++ 11.0 DebugCRT (x86)" merge module in InstalledSheild and it worked. Hope this will be helpful for someone else.
In my case one unmanaged dll was depending on another which was missing. In that case the error will point to the existing dll instead of the missing one which can be really confusing.
That is exactly what had happen in my case. Hope this helps someone else.
If the DLL and the .NET projects are in the same solution and you want to compile and run both every time, you can right click the properties of the .NET project, Build events, then add something like the following to Post-build event command line:
copy $(SolutionDir)Debug\MyOwn.dll .
It's basically a DOS line, and you can tweak based on where your DLL is being built to.
I think your unmanaged library needs a manifest.
Here is how to add it to your binary. and here is why.
In summary, several Redistributable library versions can be installed in your box but only one of them should satisfy your App, and it might not be the default, so you need to tell the system the version your library needs, that's why the manifest.
Setup: 32-bit Windows 7
Context: Installed a PCI-GPIB driver that I was unable to communicate through due to the aforementioned issue.
Short Answer: Reinstall the driver.
Long Answer:
I also used Dependency Walker, which identified several missing dependency modules. Immediately, I thought that it must have been a botched driver installation. I didn't want to check and restore each missing file.
The fact that I was unable to find the uninstaller under Programs and Features of the Control Panel is another indicator of bad installation. I had to manually delete a couple of *.dll in \system32 and registry keys to allow for driver re-installation.
Issue fixed.
The unexpected part was that not all dependency modules were resolved. Nevertheless, the *.dll of interest can now be referenced.
I have come across the same problem, In my case I had two 32 bit pcs.
One with .NET4.5 installed and other one was fresh PC.
my 32-bit cpp dll(Release mode build) was working fine with .NET installed PC but Not with fresh PC where I got the below error
Unable to load DLL 'PrinterSettings.dll': The specified module could not be
found. (Exception from HRESULT: 0x8007007E)
finally,
I just built my project in Debug mode configuration and this time my
cpp dll was working fine.
Also faced the same problem when using unmanaged c/c++ dll file in c# environment.
1.Checked the compatibility of dll with 32bit or 64bit CPU.
2.Checked the correct paths of DLL .bin folder, system32/sysWOW64 , or given path.
3.Checked if PDB(Programme Database) files are missing.This video gives you ans best
undestand about pdb files.
When running 32-bit C/C++ binary code in 64bit system, could arise this because of platform incompatibility. You can change it from Build>Configuration manager.
I faced the same problem when import C++ Dll in .Net Framework +4, I unchecked Project->Properties->Build->Prefer 32-bit and it solved for me.
It has nothing to do with dependencies if you checked all dependencies and you know you got them all, it has nothing to do with the file being in the wrong directory either or incorrect ARGUMENTS passed to dll, the DLL Fails to load using LoadLibrary itself.. you could check the address returned from LoadLibrary is always 0x0000000 (not loaded).
I couldn't figure this error out either it worked fine on Windows 7, but on Windows 10 it doesn't work. I fixed the problem though it had nothing to do with missing dependencies or Runtime redistributable packs.
The problem was I had to pack the DLL with upx and it started working again.
Something with the file being unpacked and compiled on old Windows XP operating system created a bad PE Header or Bad file format or something, but packing it with UPX did the trick works fine now and the DLL got 3x smaller haha.
I got this error for one C++ project in our solution, and only on our buildmaster's machine. The rest of us could build it with no problem.
In our case it was because that particular project had <WindowsTargetPlatformVersion> in the .vcxproj file set to "10.0" vs. "10.0.18362.0" as in all our other C++ projects.
Not specifying the entire SDK version number seems to have allowed MSBuild to choose the newest(?) SDK and associated build tools.
Our buildmaster likely had the remnants of a newer SDK on his machine, and MSBuild was trying to use it (and thus RC.exe was not found).
In any case, bringing up the project's property page and changing Configuration Properties > General > Windows SDK Version to "10.0.18362.0" (or whichever specific version of the SDK you have installed) for all of the project's configurations/platforms did the trick.
I have a dll library with unmanaged C++ API code I need to use in my .NET 4.0 application. But every method I try to load my dll I get an error:
Unable to load DLL 'MyOwn.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
I have read and tried several solutions I have found on the internet. Nothing works..
I have tried using following methods:
[DllImport("MyOwn.dll", CallingConvention = CallingConvention.Cdecl)]
[return: MarshalAs((UnmanagedType.I4))]
public static extern Int32 MyProIni(string DBname, string DBuser_pass,
string WorkDirectory, ref StringBuilder ErrorMessage);
When I tried following this article and when I run this example (from the downloaded code) it runs without a problem (the dll used is in the bin/debug folder)
I have copied my dll (along with all the files the it depends on into my bin folder).
I also tried this approach but got the same error:
[DllImportAttribute(MyOwnLibDllPath, EntryPoint="TMproIni")]
[return: MarshalAs(UnmanagedType.I4)]
public static extern int MyproIni(string DBname, string DBuser_pass,
string WorkDirectory, ref StringBuilder ErrorMessage);
Any suggestions?
From what I remember on Windows the search order for a dll is:
Current Directory
System folder, C:\windows\system32 or c:\windows\SysWOW64 (for 32-bit process on 64-bit box).
Reading from the Path environment variable
In addition I'd check the dependencies of the DLL, the dependency walker provided with Visual Studio can help you out here, it can also be downloaded for free: http://www.dependencywalker.com
You can use the dumpbin tool to find out the required DLL dependencies:
dumpbin /DEPENDENTS my.dll
This will tell you which DLLs your DLL needs to load. Particularly look out for MSVCR*.dll. I have seen your error code occur when the correct Visual C++ Redistributable is not installed.
You can get the "Visual C++ Redistributable Packages for Visual Studio 2013" from the Microsoft website. It installs c:\windows\system32\MSVCR120.dll
In the file name, 120 = 12.0 = Visual Studio 2013.
Be careful that you have the right Visual Studio version (10.0 = VS 10, 11 = VS 2012, 12.0 = VS 2013...) right architecture (x64 or x86) for your DLL's target platform, and also you need to be careful around debug builds. The debug build of a DLL depends on MSVCR120d.dll which is a debug version of the library, which is installed with Visual Studio but not by the Redistributable Package.
The DLL has to be in the bin folder.
In Visual Studio, I add the dll to my project NOT in References, but "Add existing file". Then set the "Copy to Output Directory" Property for the dll to "Copy if newer".
This is a 'kludge' but you could at least use it to sanity-test:
Try hard-coding the path to the DLL in your code
[DllImport(#"C:\\mycompany\\MyDLL.dll")]
Having said that; in my case running dumpbin /DEPENDENTS as suggested by #anthony-hayward, and copying over 32-bit versions of the DLLs listed there into my working directory solved this problem for me.
The message is just a bit misleading, becuase it isn't "my" dll that can't be loaded - it's the dependencies
Try to enter the full-path of the dll.
If it doesn't work, try to copy the dll into the system32 folder.
"Unable to load DLL 'xxx.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)" means the file CAN be found BUT it's not able to load it. Try to copy the DLL file to the root folder of your application, some DLL libraries need to be available in the root folder of the application in order for it to work. Or check if there are any other depending DLL files required by it.
"Cannot find DLL 'xxx.dll': ..." means the file CANNOT be found. Try to check the path. For example, [DllImport(#"\Libraries\Folder\xxx.dll")]
Ensure that all dependencies of your own dll are present near the dll, or in System32.
Turn on the fusion logging, see this question for lots of advice on how to do that. Debugging mixed-mode apps loading problems can be a right royal pain. The fusion logging can be a big help.
Make sure you set the Build Platform Target to x86 or x64 so that it is compatible with your DLL - which might be compiled for a 32 bit platform.
There is one very funny thing (and has a technical relevance) which might waste your hours so thought of sharing it here -
I created a console application project ConsoleApplication1 and a class library project ClassLibrary1.
All the code which was making the p/invoke was present in ClassLibrary1.dll. So before debugging the application from visual studio I simply copied the C++ unmanaged assembly (myUnmanagedFunctions.dll) into the \bin\debug\ directory of ClassLibrary1 project so that it can be loaded at run-time by the CLR.
I kept getting the
Unable to load DLL
error for hours. Later on I realized that all such unmanaged assemblies which are to be loaded need to be copied into the \bin\debug directory of the start-up project ConsoleApplication1 which is usually a win form, console or web application.
So please be cautious the Current Directory in the accepted answer actually means Current Directory of main executable from where you application process is starting. Looks like an obvious thing but might not be so at times.
Lesson Learnt - Always place the unamanaged dlls in the same directory as the start-up executable to ensure that it can be found.
I had the same problem when I deployed my application to test PC. The problem was development PC had msvcp110d.dll and msvcr110d.dll but not the test PC.
I added "Visual Studio C++ 11.0 DebugCRT (x86)" merge module in InstalledSheild and it worked. Hope this will be helpful for someone else.
In my case one unmanaged dll was depending on another which was missing. In that case the error will point to the existing dll instead of the missing one which can be really confusing.
That is exactly what had happen in my case. Hope this helps someone else.
If the DLL and the .NET projects are in the same solution and you want to compile and run both every time, you can right click the properties of the .NET project, Build events, then add something like the following to Post-build event command line:
copy $(SolutionDir)Debug\MyOwn.dll .
It's basically a DOS line, and you can tweak based on where your DLL is being built to.
I think your unmanaged library needs a manifest.
Here is how to add it to your binary. and here is why.
In summary, several Redistributable library versions can be installed in your box but only one of them should satisfy your App, and it might not be the default, so you need to tell the system the version your library needs, that's why the manifest.
Setup: 32-bit Windows 7
Context: Installed a PCI-GPIB driver that I was unable to communicate through due to the aforementioned issue.
Short Answer: Reinstall the driver.
Long Answer:
I also used Dependency Walker, which identified several missing dependency modules. Immediately, I thought that it must have been a botched driver installation. I didn't want to check and restore each missing file.
The fact that I was unable to find the uninstaller under Programs and Features of the Control Panel is another indicator of bad installation. I had to manually delete a couple of *.dll in \system32 and registry keys to allow for driver re-installation.
Issue fixed.
The unexpected part was that not all dependency modules were resolved. Nevertheless, the *.dll of interest can now be referenced.
I have come across the same problem, In my case I had two 32 bit pcs.
One with .NET4.5 installed and other one was fresh PC.
my 32-bit cpp dll(Release mode build) was working fine with .NET installed PC but Not with fresh PC where I got the below error
Unable to load DLL 'PrinterSettings.dll': The specified module could not be
found. (Exception from HRESULT: 0x8007007E)
finally,
I just built my project in Debug mode configuration and this time my
cpp dll was working fine.
Also faced the same problem when using unmanaged c/c++ dll file in c# environment.
1.Checked the compatibility of dll with 32bit or 64bit CPU.
2.Checked the correct paths of DLL .bin folder, system32/sysWOW64 , or given path.
3.Checked if PDB(Programme Database) files are missing.This video gives you ans best
undestand about pdb files.
When running 32-bit C/C++ binary code in 64bit system, could arise this because of platform incompatibility. You can change it from Build>Configuration manager.
I faced the same problem when import C++ Dll in .Net Framework +4, I unchecked Project->Properties->Build->Prefer 32-bit and it solved for me.
It has nothing to do with dependencies if you checked all dependencies and you know you got them all, it has nothing to do with the file being in the wrong directory either or incorrect ARGUMENTS passed to dll, the DLL Fails to load using LoadLibrary itself.. you could check the address returned from LoadLibrary is always 0x0000000 (not loaded).
I couldn't figure this error out either it worked fine on Windows 7, but on Windows 10 it doesn't work. I fixed the problem though it had nothing to do with missing dependencies or Runtime redistributable packs.
The problem was I had to pack the DLL with upx and it started working again.
Something with the file being unpacked and compiled on old Windows XP operating system created a bad PE Header or Bad file format or something, but packing it with UPX did the trick works fine now and the DLL got 3x smaller haha.
I got this error for one C++ project in our solution, and only on our buildmaster's machine. The rest of us could build it with no problem.
In our case it was because that particular project had <WindowsTargetPlatformVersion> in the .vcxproj file set to "10.0" vs. "10.0.18362.0" as in all our other C++ projects.
Not specifying the entire SDK version number seems to have allowed MSBuild to choose the newest(?) SDK and associated build tools.
Our buildmaster likely had the remnants of a newer SDK on his machine, and MSBuild was trying to use it (and thus RC.exe was not found).
In any case, bringing up the project's property page and changing Configuration Properties > General > Windows SDK Version to "10.0.18362.0" (or whichever specific version of the SDK you have installed) for all of the project's configurations/platforms did the trick.
Periodically I am getting the following exception:
Unable to load DLL 'SQLite.Interop.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
I am using 1.0.82.0. version, installing it with nuget in VS2010, OS Win7 64.
Once exception starts to appear, it appears constantly - in debug and release and running application within or outside VS.
The only way to stop it is logoff and logon. The exception is not thrown and dll is loaded.
It can work for days, but then it can break again.
Has anyone seen something like this and is there a solution for it?
I know I'm late to the party but I had this issue right after I pulled down latest x86/x64 today (version 1.0.88.0). My local IIS in VS2012 runs 32bit by default and there's no easy way to switch to x64. My production server runs 64bit.
Anyway I installed the NuGet package to a DLL project and I got this error. What I had to do to get it working I had to install it to the main site project, too. Even if it doesn't touch SQLite classes at all.
My guess is that SQLite uses the entry assembly to detect which version of Interop to load.
I had this problem because a dll I was using had Sqlite as a dependency (configured in NuGet with only the Sqlite core package.). The project compiles and copies all the Sqlite dll-s except the 'SQLite.Interop.dll' (both x86 and x64 folder).
The solution was very simple: just add the System.Data.SQLite.Core package as a dependency (with NuGet) to the project you are building/running and the dll-s will be copied.
So, after adding the NuGet the deployment doesn't copy down the Interops. You can add this to your csproj file and it should fix that behavior:
<PropertyGroup>
<ContentSQLiteInteropFiles>true</ContentSQLiteInteropFiles>
<CopySQLiteInteropFiles>false</CopySQLiteInteropFiles>
<CleanSQLiteInteropFiles>false</CleanSQLiteInteropFiles>
<CollectSQLiteInteropFiles>false</CollectSQLiteInteropFiles>
</PropertyGroup>
If you look in the source for NuGet for SQLite you can see what these are doing specifically. This allowed me to get a deploy working with ASP.Net Core.
I had this same problem when using SQLite in a WPF project whose platform target was Any CPU. I fixed it by following the following steps:
Open the project designer in Visual Studio. Details on how to do it can be found here.
Click on the Build tab.
Disable the prefer 32-bit option.
Alternatively, you could just set the platform target to x86 or x64. I think this problem is caused by the System.Data.SQLite library using the platform target to get the location of the 'SQLite.Interop.dll' file.
UPDATE:
In case the project designer cannot be reached, just open the project (*.csproj) file from a text editor and add the value <Prefer32Bit>false</Prefer32Bit> into the <PropertyGroup>...</PropertyGroup> tag.
Example code
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>[Set by Visual Studio]</ProjectGuid>
<OutputType>Exe</OutputType>
<AppDesignerFolder>Properties</AppDesignerFolder>
<RootNamespace>[Set by Visual Studio]</RootNamespace>
<AssemblyName>[Set by Visual Studio]</AssemblyName>
<TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
<FileAlignment>[Set by Visual Studio]</FileAlignment>
<!--Add the line below to your project file. Leave everything else untouched-->
<Prefer32Bit>false</Prefer32Bit>
</PropertyGroup>
This is how I fixed it in my project.
It was working, and when a colleague submitted his changes, I received the "Unable to load DLL 'SQLite.Interop.dll'" exception.
Diffing the project's .csproj file, this was in the NON-WORKING version:
<ItemGroup>
<Content Include="x64\SQLite.Interop.dll" />
<Content Include="x86\SQLite.Interop.dll" />
</ItemGroup>
And this is what the WORKING version had:
<ItemGroup>
<Content Include="x64\SQLite.Interop.dll">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</Content>
<Content Include="x86\SQLite.Interop.dll">
<CopyToOutputDirectory>Always</CopyToOutputDirectory>
</Content>
</ItemGroup>
After reverting back, I didn't receive the exception. The DLL files were dumped in the appropriate Debug\x64 (etc) folders.
When you get in this state, try performing a Rebuild-All. If this fixes the problem, you may have the same issue I had.
Some background (my understanding):
SQLite has 1 managed assembly (System.Data.SQLite.dll) and several
platform specific assemblies (SQLite.Interop.dll). When installing
SQLite with Nuget, Nuget will add the platform specific assemblies to your project
(within several folders: \x86, \x64), and configures these
dlls to "Copy Always".
Upon load, the managed assembly will search for platform
specific assemblies inside the \x86 and \x64 folders. You can see
more on that here. The exception is this managed
assembly attempting to find the relevant (SQLite.Interop.dll) inside
these folders (and failing).
My Scenario:
I have 2 projects in my solution; a WPF app, and a class library. The WPF app references the class library, and the class library references SQLite (installed via Nuget).
The issue for me was when I modify only the WPF app, VS attempts to do a partial rebuild (realizing that the dependent dll hasn't changed). Somewhere in this process, VS cleans the content of the \x86 and \x64 folders (blowing away SQLite.Interop.dll). When I do a full Rebuild-All, VS copies the folders and their contents correctly.
My Solution:
To fix this, I ended up adding a Post-Build process using xcopy to force copying the \x86 and \x64 folders from the class library to my WPF project \bin directory.
Alternatively, you could do fancier things with the build configuration / output directories.
I had the same issue running Visual Studio Express 2013. I tried several solutions mentioned here and elsewhere to no avail. I hope this fix helps others.
I fixed it by using the DeploymentItem attribute on my test class that tests the SQLite-based service.
Example:
[TestClass]
[DeploymentItem(#"x86\SQLite.Interop.dll", "x86")] // this is the key
public class LocalStoreServiceTests
{
[TestMethod]
public void SomeTestThatWasFailing_DueToThisVeryIssue()
{
// ... test code here
}
}
This causes the needed SQLite.Interop.dll to get copied to the x86 directory within the appropriate "TestResults" folder.
All is green. All is good.
Updating NuGet from Tools -> Extension and updates and reinstalling SQLite.Core with the command PM> Update-Package -reinstall System.Data.SQLite.Core fixed it for me.
old project file format
i.e. projects beginning with <Project ToolsVersion="3.5" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
Add the following to your csproj on your "main"/root project
<PropertyGroup>
<ContentSQLiteInteropFiles>true</ContentSQLiteInteropFiles>
<CopySQLiteInteropFiles>false</CopySQLiteInteropFiles>
<CleanSQLiteInteropFiles>false</CleanSQLiteInteropFiles>
<CollectSQLiteInteropFiles>false</CollectSQLiteInteropFiles>
</PropertyGroup>
new SDK project file format
i.e. projects beginning with <Project Sdk="Microsoft.NET.Sdk.*">
Add PrivateAssets="none" to each ProjectReference/PackageImport in the dependency chain down to the System.Data.Sqlite PackageImport
ex:
<PackageReference Include="System.Data.SQLite.Core" Version="1.0.110" PrivateAssets="none"/>
I had a similar issue in a multiple projects solution. The SQLite.Interop.dll was necessary for one of the plugins distributed with the software using ClickOnce.
As far as debugging in visual studio everything worked fine, but the deployed version was missing the folders x86/ and x64/ containing that DLL.
The solution to have it work after deployment using ClickOnce was to create in the startup project of the solution (also the one being published) these two subfolder, copy into them the DLLs and set them as Content Copy Always.
This way the ClickOnce publishing tool automatically includes these files and folders in the manifest and deploys the software with them
There are really a lot of answers here, but mine is simple and clear with no-GAC-playing-around.
The problem was, the executable File needs a copy of the right SQLite.Interop.dll (x86 or x64) to access our Database.
Mostly architectures have layers and in my case the Data Layer has the required DLL for SQLite Connection.
So i simple put a post build script into my Data Layer Solution and everything worked fine.
TL;DR;
Set all Projects of your solution to x86 or x64 in the build options.
Add following Post-Build-Script to the Project with the SQLite nuget Package:
xcopy "$(TargetDir)x64" "$(SolutionDir)bin\Debug\" /y
Of course you have to change the script for Release Build and x86 builds.
STL;DR;
Put your SQLite.Interop.dll next to the *.exe File.
The default installation of the multi-architecture (x86, x64) version of SQLite from NuGet exhibits the behavior that you described. If you would like to load the correct version for actual architecture that the .NET runtime chose to run your application on your machine, then you can give the DLL loader a hint about where to locate the correct library as follows:
Add a declaration for the kernel32.dll function call to SetDLLDirectory() before your Program.Main():
[System.Runtime.InteropServices.DllImport("kernel32.dll", CharSet = System.Runtime.InteropServices.CharSet.Unicode, SetLastError = true)]
[return: System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)]
static extern bool SetDllDirectory(string lpPathName);
Then use your own method for determining the correct subdirectory to find the architecture specific version of 'SQLite.Interop.dll'. I use the following code:
[STAThread]
static void Main()
{
int wsize = IntPtr.Size;
string libdir = (wsize == 4)?"x86":"x64";
string appPath = System.IO.Path.GetDirectoryName(Application.ExecutablePath);
SetDllDirectory(System.IO.Path.Combine(appPath, libdir));
even if it is an old post, I'd like to share the solution that I found here:
http://system.data.sqlite.org/index.html/info/54e52d4c6f
If you don't want to read all the issue, the solution is to copy the file "msvcr100.dll" (that can be found in Windows\System32 directory) in the same path as SQLite.Interop.dll.
I would advice to read the issue to understand why, and to include the file in your setup but to install it only if the error occurs, I made it an optional component selectable in the setup options.
HTH,
Formentz
I don't know why this has not been included yet, but I had to do the research and find this out for myself, so hopefully someone will find this answer and be saved the trouble. This was for a WPF app. It worked fine on my Dev box, but did not work on the computer where I was copying it and got the Unable to load DLL 'SQLite.Interop.dll' error. I ported over all of its associated directories and files, directly from my "Debug" folder to this other computer when I got the same error as the OP when I ran it. My "bin" folder that contained my DLLs had been copied to "Debug\bin" and all were included, along with my application files when I did my copying to the other computer using this path, so it was not missing any files.
Things I saw said in other answers that did not apply:
I did not use the NuGet package or need to create x86 or x64 folders that it seems that NuGet package creates. My DLLs (System.Data.SQLite and SQLite.Interop.dll, along with System.Data.SQLite.config) are in the "bin" folder in my project and were copied in manually (create "bin" folder in Solution Explorer in VS, paste DLLs into this folder in Windows Explorer, use Add > Existing Item to bring files into VS folder/project). Then I reference them as Referenced Assemblies in my project using that location ("References" > "Add Reference", and browse to one, rinse, repeat for the rest). This ensures my project knows exactly where they are.
I did not need to reference any SQLite DLL file in my app.config or even touch my MyProject.csproj file.
I did not even need to specify a particular processor! My project's build is for "Any CPU", even though I have only mixed or 64-bit DLLs and will only be running on Windows 7+, which are 64-bit OSes. (no x86-only/32-bit solely DLLs)
I was already specifying them as "Content" and "copy if newer" for these DLLs when I experienced the OP's error.
What I found was this, from https://system.data.sqlite.org/index.html/doc/trunk/www/faq.wiki#q20 :
(11) Why do I get a DllNotFoundException (for "sqlite3.dll" or "SQLite.Interop.dll") when trying to run my application?
Either the named dynamic link library (DLL) cannot be located or it cannot be loaded due to missing dependencies. Make sure the named dynamic link library is located in the application directory or a directory along the system PATH and try again. Also, be sure the necessary Visual C++ runtime redistributable has been installed unless you are using a dynamic link library that was built statically linked to it.
Emphasis mine on that bolded part inside the paragraph. The target computer was fresh and had no programs loaded except .NET 4.0. Once I installed C++, it was able to complete the commands to SQLite. This should have been one of the first FAQs and part of the pre-requisities, but it was buried at #11. My development computer already had it loaded because it came with Visual Studio, so that's why it worked, there.
Download:
Visual C++ Redistributable for Visual Studio 2015:
https://www.microsoft.com/en-us/download/details.aspx?id=48145
Update 3 (cumulative update):
https://www.microsoft.com/en-us/download/details.aspx?id=53587
As the SQLite wiki says, your application deployment must be:
So you need to follow the rules. Find dll that matches your target platform and put it in location, describes in the picture. Dlls can be found in YourSolution/packages/System.Data.SQLite.Core.%version%/.
I had problems with application deployment, so I just added right SQLite.Interop.dll into my project, the added x86 folder to AppplicationFolder in setup project and added file references to dll.
I had the same issue. Please follow these steps:
Make sure you have installed System.Data.SQLite.Core package by
SQLite Development Team from NuGet.
Go to project solution and try to locate build folder inside packages folder
Check your project framework and pick the desired SQLite.Interop.dll and place it in your debug/release folder
Reference
Copy "SQLite.Interop.dll" files for both x86 and x64 in debug folder. these files should copy into "x86" and "x64 folders in debug folder.
You could also get this error if you are trying to run a 32 bit dll, in a 64 bit project.
I got this when I have placed the same file(SQLite.Interop.dll in 32 bit version) in both the x86 and x64 folder.
If you download correct binary for SQLite then copy SQLite.Interop.dll into your Release or Debug folder according to your project build option.
I have started using Costura.Fody to package (.net) assemblies and embed and preload native dlls. This also helps later, with distribution as you can send one file.
Install Costura Fody from Nuget.
In your C# project create a folder called costrua32. In there add any native dlls you which C# to load.
Once you have added them to this folder. Click on the properties window and change build action to "Embedded Resource"
Finally you need to amend the XML file called FodyWeavers.xml as follows. Here I am specifying load the sql dll first. (note you drop the .dll)
Weavers
Costura
PreloadOrder
SQLite.Interop
tbb_debug
tbb
/PreloadOrder>
/Costura
/Weavers
The advantage of this is that you do not have to write any pre or post build events, and the end product is totally encapsulated in to one larger file.
Also added the dll to the test project (through Nuget Manager) and it fixed it.
Could there be contention for the assembly? Check to see whether there's another application with a file lock on the DLL.
If this is the reason, it should be easy to use a tool like Sysinternal's Process Explorer to discover the offending program.
HTH,
Clay
I had this problem because Visual C++ 2010 redistributable no installed in my PC.if you have not already installed Visual c++ 2010 redistributable Download and install this(check x86 or 64 dll).
I got the same problem. However, finally, I can fix it. Currently, I use Visual Studio 2013 Community Edition. I just use Add->Existing Item... and browse to where the SQLite.Data.SQLite files are in (my case is 'C:\Program Files (x86)\System.Data.SQLite\2013\bin'). Please don't forget to change type of what you will include to Assembly Files (*.dll; *.pdb). Choose 'SQLite.Interop.dll' in that folder. From there and then, I can continue without any problems at all. Good luck to you all. ^_^
P.S. I create web form application. I haven't tried in window form application or others yet.
Try to set the platform target to x86 or x64 (and not Any CPU) before you build:
Project->Properties->Build->Platform target in Visual Studio.
Copy SQLite.Interop.dll in project directory.
src\
project\
bin\ <-- Past in bin
x64\
SQLite.Interop.dll <-- Copy this if 64
x86\
SQLite.Interop.dll <-- Copy this if 32
I've struggled with this for a long time, and, occasionally, I found that the test setting is incorrect. See this image:
I just uncheck the test setting, and the issue disappears. Otherwise, the exception will occurs.
Hopefully, this will help someone.
Not sure it's the root cause.
My application is a web application (ASP.NET MVC) and I had to change the application pool to run under LocalSystem instead of ApplicationPoolIdentity. To do this:
Open IIS Manager
Find the Application Pool your site is running under.
Click Advanced Settings from the actions
Change Identity to LocalSystem
I have no idea why this fixes the issue.
My situation was a little unique. I was running an application inside a docker container and kept getting the following error
System.DllNotFoundException : Unable to load shared library 'SQLite.Interop.dll' or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: libSQLite.Interop.dll: cannot open shared object file: No such file or directory
So I set LD_DEBUG=libs to find out what folders System.Data.SQLite.dll was looking in to find SQLite.Interop.dll.
You can find info on setting LD_DEBUG here: http://www.bnikolic.co.uk/blog/linux-ld-debug.html
Once I did that I realized that SQLite.Interop.dll was being found just fine. The DLL that wasn't being found was libSQLite.Interop.dll. I should have read the entire error message.
Hours of Googling later I found this guide on how to compile the missing DLL from the SQLite source code.
Note that the file that was actually missing was libSQLite.Interop.dll.so
Anyway when you compile the source code you get libSQLite.Interop.so which you need to rename to libSQLite.Interop.dll.so and put it in the directory that it's looking in which you can find by setting LD_DEBUG.
For me the directory that System.Data.SQLite.dll was looking in was /usr/lib/x86_64-linux-gnu/
Upgrading to Visual Studio 2019 ver. 16.10 caused the issue for me, where msbuild reported the following for the System.Data.SQLite.Core-package:
CopySQLiteInteropFiles:
Skipping target "CopySQLiteInteropFiles" because it has no outputs.
https://github.com/dotnet/msbuild/issues/6493
Microsoft says the bug has been fixed with ver. 16.10.4. Now just have to wait for AppVeyor to update their Visual Studio Images (Until then one can use Previous Visual Studio 2019).
Now AppVeyor is using broken dotnet-build-engine for both current and previous Visual Studio 2019-image. Now one have to explicit install dotnet sdk ver. 5.0.302:
Invoke-WebRequest -Uri 'https://dot.net/v1/dotnet-install.ps1' -UseBasicParsing -OutFile "$env:temp/dotnet-install.ps1"; & $env:temp\dotnet-install.ps1 -Architecture x64 -Version 5.0.302 -InstallDir "$env:ProgramFiles\dotnet"
I have created a dll that will be used by multiple applications, and have created an installer package that installs it to the program files, as well as adds it to the Global Assembly Cache.
The dll itself uses log4net, and requires a xml file for the logging definitions.
Therefore when the installer is run, the following files get copied to the install directory within program files:
The main dll that I developed
- The Log4Net.dll
- the Log4Net.xml file
I am now experiencing a problem. I have created a test console application for experimentation. I have added my dll as a reference, and set the 'local copy' flag to false.
When I compile the test console exe however, I noticed that it has copied the log4net.dll and log4net.xml files to the bin directory. And when running the test console, it appears that it will only work if the log4net.dll is in the same directory as the exe. This is dispite the fact that the test console application does not use log4net, only the dll that was added as a reference does.
Is there some way to have it so that the log4net.dll & xml files used will be the ones that were installed to the program files, rather than any application needed to copy over local copies? The applications that will be using my dll will not be using log4net, only the dll that they are referencing uses it.
Many thanks
Don't install into the Global Assembly Cache! Even if your library dll is used by multiple applications each should have it's own local copy. Otherwise you get into a whole world of pain for saving a few KB of disk space.
Always copy the required dlls locally. If you are really sure that the application won't need it you can simply delete the unnessesary dlls later or don't include them in the installer. But if your application will call ANY reference there it will crash at runtime. So best option is to leave them there (after all they WERE referenced for a reason).
No, it's not possible (at least not without much efford) to have .Net load dlls from arbitrary locations on the disk. And it should be this way (look up DLL-hell if you want to know why).
I suspect your problem is the configuration. You must use fully qualified names if you want it to work from the GAC. As per the documentation at http://logging.apache.org/log4net/release/faq.html:
"When loading an assembly from the GAC the fully qualified assembly name, including the version, culture and public key must be specified. This is in the standard syntax supported by System.Type.GetType. See the next FAQ on how to get the version and public key for an assembly."
I managed to resolve this by adding Log4net.dll to the GAC as well. It will now run without needing a local copy the dll.
It does however require a local copy of the XML file, to correctly log.
How can I get the (physical) installed path of a DLL that is (may be) registered in GAC? This DLL is a control that may be hosted in things other than a .Net app (including IDEs other than VS...).
When I use System.Reflection.Assembly.GetExecutingAssembly().Location, it gives path of GAC folder in winnt\system32 - or in Design mode in VS gives the path to the VS IDE.
I need to get the path where physical dll is actually installed - or the bin/debug or (release) folder for VS.
Reason is that there is an XML file I need to get at in this folder, with config setting that are used both in design mode and at runtime.
Or how is it best to handle this scenario? I have a dubious network location I am using for design mode at the moment... (Don't think that ApplicationData folder is going to cut it (but have the .Net version soved as that's installed via ClickOnce ans can use the Clickonce Data folder) )
If something gets put in the GAC, it actually gets copied into a spot under %WINDIR%\assembly, like
C:\WINDOWS\assembly\GAC_32\System.Data\2.0.0.0__b77a5c561934e089\System.Data.dll
I assume you're seeing something like that when you check the Location of the assembly in question when it's installed in the GAC. That's actually correct. (In .NET 1.1 there was a "Codebase" listed when you looked at a GAC assembly's properties, but that was only to show you where the original file was located when you ran gacutil - it didn't actually indicate what would be loaded.) You can read more about that here.
Long story short, you may not be able to do what you want to do. Instead of looking in relation to some assembly that's being loaded (Assembly.GetExecutingAssembly()), you might want to switch the behavior to look relative to the primary application assembly (Assembly.GetEntryAssembly()) or put the file in some well-known location, possibly based on an environment variable that gets set.
After the assembly is shadow copied into the Global Assembly cache, i don't think there is any metadata to traceback the location of the source assemblies.
What are you trying to achieve by deploying in GAC? If its just for the sake of CLR for resolving purposes, then there is an alternate way that solves your problem.
Don't gac install the dll, rather add the following key in the registry, (this registry location is looked up by CLR when trying to resolve assemblies)
32 bit OS : HKEY_LOCAL_MACHINE\SOFTWARE\\Microsoft\.NETFramework\v4.0.30319\AssemblyFoldersEx\foo
64 bit OS : HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319\AssemblyFoldersEx\foo
For the foo key (Use your favourite name instead of foo), you will see a Key Name "Default". Double click it and set the value to wherever your assembly exists. (absolute path is preferred)
Now from Visual Studio, your client should be able to see your assemblies in the "Add Reference" Dialog and can use it.
Now coming to your actual problem,
Assembly.GetExecutingAssembly() will return the path of the location where the insatlled dll's are present. Find the XML file from there. :)
Note: In the registry key the 4.0.30319 is the version of the .NET Framework your application targets. Use whatever version your application targets instead.
Do you have the option of embedding a resource to this DLL? That way, it doesn't really matter where the DLL is located on disk, because the XML file will follow it. You can then do something like this:
Stream s = Assembly.GetExecutingAssembly().GetManifestResourceStream("MyProject.MyXmlFile.xml");
XmlDocument d = new XmlDocument();
using (StreamReader r = new StreamReader(s))
{
d.LoadXml(r.ReadToEnd());
}
If you are looking for the physical location where your GACed DLL is saved in the file system, try this:
start-->run-->c:\windows\assembly\gac
If you don't find your DLL related folder in there, you can do a "Up" folder in windows explorer to display everything in c:\windows\assembly as folder structures. You can then look for your DLL under GAC_MSIL or any other folder out there....
Cheers,
Sri