I downloaded a package from SourceForge, PlanEph, which has 64 and 32 bit DLLs for C#. I got the 32 bit included C# demo to work by putting the DLL in my bin/Debug directory (I'm using Visual Studio 2015 Community) and adding the DLL as a reference.
Then I tried to make my own version of the demo in a separate solution, and got the System.DllNotFoundException. Various experimentation lead me to believe I can't have two identical namespace names anywhere in my Visual Studio installation, so I erased everything and started over.
I made a directory C\GJAbin, put the DLL in it, and added it to the system Path variable. I also put a helloWorld type program in that dir and executed it from the command line to verify the directory really was in the path. Then I recreated the demo solution, added the DLL as a resource, and built the solution "successfully". Then I ran it and got the System.DllNotFoundException.
So I can't understand why the DLL is being found when compiling but not at run time.
Go to project settings, go to "publish" tab and on the top most button (labeled something like "application files"). Chose "Show all files" checkbox if you don't see your DLL. Set the DLL's publish status to "Include" (NOT "Include (Auto)"!!) and publish it again.
Now the DLL should be inside the publish folder.
So I can't understand why the DLL is being found when compiling but not at run time.
Locating the assembly at compile time is done differently (by MSBuild) than at runtime (by the CLR).
At compile time, MSBuild has specific search paths that it knows about, or in most cases like this, there will be something in your project file telling MSBuild where to look for the file. Usually the <Reference> has a <HintPath>.
At runtime, the CLR will attempt to find the assembly from its own set of well-known paths. It will look in your app's config file (if applicable), then in the Global Assembly Cache (GAC), then in your app's root directory. Much more detail on this is available here.
You can tell MSBuild to copy the reference to your build output directory (usually the same as your app root directory when running). In VS, you can do this by selecting the reference and looking at the Properties tool window (or press F4 by default). Set the CopyLocal state to True. In the project file, this will add a <Private>True</Private> on the <Reference>.
You can also add the assembly to the GAC using the gacutil tool, but this does make it harder if you want to share your app with others. Usually it's preferable to keep a copy in your app root directory.
If it's still not working, you can also see the log for how the runtime is trying to find this assembly. The fuslogvw.exe tool in the Windows SDK (you can run it from the VS command prompt and it will be on the %PATH%) allows you to enable logging for assembly loads. You do need to be able to run this as an administrator to configure the setting.
As you can see in the screenshot, you can either log the results in the exception (so that you can see it while debugging), or you can log it to a file on disk (so you can see it whenenver).
The problem turned out to be an unfortunate interaction among the way the author chose names and the way Visual Studio displays information and error messages. The author created a c# dll Astronomy.PlanEph32.dll containing a namespace PlanEph32, which which was really just a wrapper for the c dll PlanEph32.dll. So all the error messages about not being able to load PlanEph32.dll were referring to not finding the c dll; the c# dll was being found just fine.
I have 3 projects in my solution and a bunch of 3rd party or company dlls. Each time I rebuild my project or clean solution, a lot of this dll's are deleted, therefore missing. It is pretty annoying to reference this dll files again and again after rebuilding. Can someone explain how to avoid this? Thanks in advance.
The bin folder is just the binary output from a build, so when you clean your solution, all the assemblies in the bin folder get deleted. You should reference the assemblies from some other location. One suggestion is to create a Shared Resources folder within your project, copy your assemblies to that folder, then reference them from that folder. This way they won't get deleted from bin on a clean/rebuild and Visual Studio will copy them there as needed.
Right-click on the References folder in your project and choose Add Reference...
Use the browse functionality to locate the assemblies you want to reference (don't worry about manually copying them to/from your bin folder)
After the reference is added, right-click on the reference in your references list and choose Properties
Make sure the Copy Local property is set to True
This will ensure that assembly is copied to your bin folder on every build.
In my case, .net framework version is the problem. I had to lower its version to 4.5 and then the projects got built properly and able to reference in other projects
As Troy explained in his answer, indeed a reference to a *.dll file, kept outside the bin folder, ensures that the dll file does not get definitively wiped out when cleanning the project.
However, just by adding a reference to the assembly might not be enough. For instance it would not work for some other file types, such as the *.pdb files as well as for the *.resources.dll files (which are typically spread in many sub-folders named after the language codes (2 letters' language code)
To depict this problem with a real life situation, I picked up an assembly for which the source code is either gone, or not compatible anymore, etc. I chose (on purpose...) a 13 years old AjaxControlToolkit composed of many component files. The picture below illustrate its composition. Every time the "Clean" command is applied to the project all these files are deleted, except the one which is the referenced assembly. Moreover having several *.resources.dll file assemblies of the same name, as in the present case, makes it inconvenient, if not possible, to add "references" to each of them from within the same project.
Nevertheless here is a pretty simple workaround:
keep this file hierarchy in a separate folder (as Troy explained in his answer)
just copy them over in the bin folder using a command line entered in the Pre-build event of the project, such as xcopy "$(SolutionDir)AjaxControlToolkit" "$(TargetDir)" /y /i /s /r /q
Hoping that will be useful to someone...
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"