I want to embed c++ native dll in set up file created with install shield limited edition.
Hint :- My application created by using c# and c++ native dll.
Here is my example :-
My c++ dll_code
extern "c" __declspec(dllexport) int function_c ()
{
int a=10;
return a;
}
My .net code
public partial class Form1 : Form
{
[DllImport(#"C:\Users\bajwa\Documents\Visual Studio 2012\Projects\c++dll\c++_dll.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
static extern int function_c();
void csharp_function()
{
int result= function_c(); // calling c++ native function
MessageBox.Show(result);
}
private void button1_Click(object sender, EventArgs e)
{
csharp_function(); // calling c# function.
}
}
When I installed this setup on my computer it runs perfectly. Because C++ native dll is placed on my computer at "C:\Users\bajwa\Documents\Visual Studio 2012\Projects\c++dll\c++_dll.dll".
But when I delete the c++ native dll from that location then it shows the error.
dll not fount at this location
Please help and solve my problem.
I think you will just need to use a relative path for the imported DLL. The easiest thing to do would be to copy the DLL to a known folder relative to the executable (maybe even the same folder) and then use that path. So if they share a folder, your code can become this:
[DllImport("c++_dll.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
static extern int function_c();
Then just modify the installer to place the dll in the correct location. To test, just change your code and move the dll over, but it should work.
Related
I want to use a C++ dll IN a c# code
example (using the c++ dll):
class Program
{
[DllImport(#"netcoreapp3.1\savedecrypter.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern string decryptSave(string o);
static void Main(string[] args)
{
string ja = "dhsabdasji";
string show = decryptSave(ja);
Console.WriteLine(show);
Console.ReadLine();
}
}
**and this is the EXAMPLE C++ dll code(im just a newbie in c++ btw)**
extern "C"
{
__declspec(dllexport) string decryptSave(string path21)
{
return path21;
}
}
i got an error when trying to call it
"System.DllNotFoundException: 'Unable to load DLL 'netcoreapp3.1\savedecrypter.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)'"
can anyone fix this for me? Would appreciate if somebody could do so.
edit : now i have enabled native code debbuging, it show this error :
Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Is possible that your 'savedecrypter' DLL has a call to another DLL that is missing in your machine. Check if you have all the required drivers, this is a common mistake when you are working with third-party 'black-box' DLL's.
I am having an issue passing a simple string from my .NET app, compiled as 64-bit, to my native DLL, also compiled as 64-bit.
C++ signature:
DllExport void SetFoo(LPWSTR foo);
C# signature:
[DllImport(Library, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
internal static extern void SetFoo(
[In][MarshalAs(UnmanagedType.LPWStr)] string foo);
Then I run the following code in C#:
X.SetFoo("some string");
When it reaches the debugger in the DLL, the value is swearing at me in Chinese: Ⴐ虘翺
When I change both the .NET and native code to 32-bit, the value I get in the debugger is the correct string. Where am I being stupid?
Minimal reproduction as a Visual Studio 2015 Solution: download here
To reproduce:
Create a new Visual Studio solution with a WinForms project.
Add a Win32 Project, of type DLL to the solution
Add the following files:
Foo.h:
extern "C" {
__declspec( dllexport ) void SetFoo(LPWSTR);
}
Foo.cpp:
#include "stdafx.h"
#include "Foo.h"
DllExport void SetFoo(LPWSTR foo)
{
}
Set a breakpoint on the opening brace in SetFoo
Add a button to the winforms form
Double click it, and call SetFoo("abc123").
Implement SetFoo:
Form1.cs:
[DllImport("Win32Project1.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
public static extern void SetFoo(string text);
Change the apps to build in 64-bit mode by opening Configuration Manager.
Set Win32Project1 to build as x64
Set WindowsFormApplication1 to build as x64, by picking platform new, pick x64, OK.
Change the output directory of WindowsFormsApplication1 to match the output directory of the other app.
Start without debugging.
Attach debugger (Ctrl+Alt+P) by setting Attach to to Managed (v4.5, v4.0) code, Native code and finding the process.
Observe value at breakpoint.
When you interpret ANSI encoded latin text as UTF-16 you see Chinese characters. That's clearly what is happening. So your C# code is sending ANSI encoded text somehow.
The p/invoke would be better written like this:
[DllImport(Library, CallingConvention = CallingConvention.Cdecl,
CharSet = CharSet.Unicode)]
internal static extern void SetFoo(string foo);
The [in] is not needed, it is the default. And the MarshalAs is pointless since you specified CharSet.Unicode. However, neither change affects the semantics.
The only sound explanations for what you describe in the question are:
The actual code is not as you have described it, or
There is a defect in the debugger.
I suggest that you change the unmanaged function to
DllExport void SetFoo(LPWSTR foo)
{
MessageBoxW(0, L"", foo, MB_OK);
}
If the message box displays the correct text then the conclusion would appear to be that the debugger is defective.
I have a C++ dll with simple function like
#ifdef BUILDING_THE_DLL
#define EXPORTED __declspec(dllexport)
#else
#define EXPORTED __declspec(dllimport)
#endif
...
EXPORTED void AddSetting(char *key, char *value)
And a C# project with function declaration:
[DllImport("pers.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void AddSetting(string key, string value);
Everything works perfectly well while C# project is build in Debug mode. In Release build an exception is fired: "An attempt was made to load a program with an incorrect format."
Any ideas?
UPD: In C# project Platform target was set to x86 in Debug mode and Any CPU in Release. I've changed to x86 in Release and it was the solution. Thanks a lot to Matt.
You need specify to use the ansi format of the string, by default. it is unicode. It should be :
[DllImport("pers.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet::Ansi)]
public static extern void AddSetting(string key, string value);
Also, if the function "AddSetting" modifies the strings, you need to use StringBuilder in C#. Please refer this MSDN article for details.
I have one project which capture images from multiple cameras which is in C++ .I want to use that project in my new project which is in C#.I had made dll of that project.My question is ,how can i use that dll in my project.I know by passing window handle to C++ dll we can use it but i dont know how to do it and what changes should i make in dll.
Please forgive ,if it is foolish question.
I had the exact problem as you and this article helped me.
http://blogs.msdn.com/b/jonathanswift/archive/2006/10/03/dynamically-calling-an-unmanaged-dll-from-.net-_2800_c_23002900_.aspx
To pass the handle, you can add another function in C++ end. Something like,
(in the header)
extern "C" __declspec(dllexport) void SetParent(HWND hWnd);
To use the SetParent in C#
class Program
{
...
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate void SetParent(IntPtr hWnd);
public void testMethod()
{
...
IntPtr getAddress = NativeMethods.GetProcAddress(pDll, "SetParent");
...
SetParent setParent = (SetParent)Marshal.GetDelegateForFunctionPointer(getAddress, typeof(SetParent));
setParent(this.Handle);
...
}
}
If your C++ project is already in a DLL you can call any functions that it exports using P/Invoke. You will have to declare the method in your C# assembly as shown below, but then you can call it like a standard static method.
[DllImport("YourDllsName.dll")]
public static extern bool FunctionThatAWindowHandleAndReturnsBool(IntPtr hWnd);
Depending on the types of parameters that your C++ DLL's functions take the marshaling of the .Net datatypes to C data types can get complicated.
I have a C# application from which I am trying to send a parameter to a C++ function. However, I am getting the error (mentioned in the subject)
C# application:
static class SegmentationFunctions
{
[DllImport("MyApplication.dll", EntryPoint = "fnmain", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
public static extern int fnmain(string search);
}
}
public partial class MainWindow:Window
{
public MainWindow()
{
InitializeComponent();
string search = "test string here";
int scommand = SegmentationFunctions.fnmain(search);
}
C++ file.h
extern "C" QUERYSEGMENTATION_API int fnmain(char query[MAX_Q_LEN]);
C++ file .cpp
extern "C" QUERYSEGMENTATION_API int fnmain(char searchc[MAX_LEN_Q])
{
do something...
}
Dependency Walker can show you what functions are effectively exported from the DLL. You will be able to see if your fnmain is there at all, or it is _fnmain instead , or has a C++ decoration in its name.
Note that by default visual studio will not copy your native output to the same folder as your managed output.
manually copy native output to your managed build folder and try again - if that is your problem then you need to change the C++ build settings to put the destination folder the same as your managed app folder.
Your code is correct - so long as the QUERYSEGMENTATION_API macro is defined correctly and your dll is in fact built as "MyApplication.dll"
I would manually run the executable from the file system - making sure that the latest exe and dll are in the same folder, and if it fails run depends.exe to figure it out.