使用 DLL 调用进入 function 时程序崩溃

Question

Code:

private void button1_Click(object sender, RoutedEventArgs e)
{
   MessageBox.Show("Enters a button click");
   // Create our OpenGL Hwnd 'control'...
   HwndHost host = new WPFOpenGLLib.OpenGLHwnd();

   // ... and attach it to the placeholder control:
   hwndPlaceholder.Child = host;
}

WPFOpenGLLib.OpenGLHwnd() is a class in a C++ DLL. I added a reference to that DLL in my C# WPF application. But when I click button1 the application crashes. Even the messageBox with »Enters a button click« does not show. Even when I use

bool a = false;
if (a)
{
   // Create our OpenGL Hwnd 'control'...
   HwndHost host = new WPFOpenGLLib.OpenGLHwnd();

   // ... and attach it to the placeholder control:
   hwndPlaceholder.Child = host;
}

its crashes.

By the way, on one computer (where I write the application) (Win7 32bit) everything works fine, on another computer (Win7 64bit) it crashes, and on yet another computer (Win7 32bit) its crashes as well.

Does anyone know what the problem is here?

Answer 1

I have not done any OpenGL stuff for a while (used to do it in C++ and win32 years ago), but a Hwnd is a window handle and like most things in C++ is just a memory address to a window, and as 64bit changes the default pointer size I assume that either the library you are using acting on behalf of C++ in the managed environment is not setup to deal with 64bit systems.

Answer 2

This sounds most likely to be some architecture mixup that causes the issues. Do you use a x64 version of the library on the x64 system or are you trying to use the 32 bit one? In later case go to the project properties (of your C# project) and set the target CPU to x64 (by default it should be Any CPU ). With the default setting your project will be executed by the 64 bit virtual machine and therefore fail to load the 32 bit library.

Once that's done, ensure all systems got the correct dependencies installed. Eg I think Microsoft never changed the .net applications' behaviour of simply crashing if the correct runtime files are missing. If that doesn't solve the issue either, there's most likely some bug (or another reason for crashing) in the initialization code of the DLL file.

Answer 3

I realize this is an old, dead thread, but if anyone else looks at this --

I have a C# application that relies on a DLL (native/clr code). When I run the application WITHOUT the DLLs it opens fine and everything looks great until you click on a button that actually calls a DLL function. The program then crashes as described in this question. Seems to me that the OP might have the DLLs on his dev machine, but does not have them on the other, mystery computers. So, program runs and seems to work, until a DLL call is made.

I was searching around to see how to check for all required DLLs at start up and stumbled onto this question. A native C++ application won't even start up if all required DLLs are not found. Is C# "delay loading" it's DLLs? Maybe.