[英]Exception when closing a Win32 dialog box in dll (from WPF application)
I have a C# application that is calling a C++ function from a DLL. 我有一个从DLL调用C ++函数的C#应用程序。 The C++ function shows a dialog box and a exit button only.
C ++函数仅显示一个对话框和一个退出按钮。
The C++ function in DLL is looking like: DLL中的C ++函数如下所示:
//the exported function for clients to call in DLL
HINSTANCE hInstance;
__declspec(dllexport) int __cdecl StartDialog(string inString)
{
hInstance = LoadLibrary(TEXT("My.dll"));
DialogBox(hInstance, MAKEINTRESOURCE(ID_DLL_Dialog), NULL, DialogProc);
return 1;
}
BOOL CALLBACK DialogProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
switch (LOWORD(wParam))
{
case IDD_BUTTON_EXIT:
DestroyWindow(hwnd);
return TRUE;
}
}
return FALSE;
}
If I call my StartDialog
function in a simple C++ program, it works. 如果我在一个简单的C ++程序中调用
StartDialog
函数,它将起作用。 I can show the dialog, and can close it properly when I click exit in my dialog. 我可以显示该对话框,并且在单击对话框中的退出时可以正确关闭它。
typedef int(__cdecl *StartDialogFunc)(string);
StartDialogFunc StartDialog = nullptr;
HINSTANCE hDll = LoadLibrary(TEXT("My.dll"));
StartDialog = (StartDialogFunc)GetProcAddress(hDll, "StartDialog");
int i = StartDialog("hello"); //this is working
cout << i;
If I call it in my C# application, after I click the exit button, the dialog closes, and give me an exception. 如果我在C#应用程序中调用它,则单击退出按钮后,对话框将关闭,并给我一个例外。 The C# code looks like:
C#代码如下所示:
[DllImport("My.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern int StartDialog(string s);
int i = StartDialog("hello"); //this causes a exception
The error message is like: 错误消息是这样的:
Debug Assertion Failed!
调试断言失败!
Program: (some paths...) My.dll
程序:(某些路径...)My.dll
File: d:\\program files (x86)\\microsoft visual studio 14.0\\vc\\include\\xmemory0
文件:d:\\ program files(x86)\\ Microsoft Visual Studio 14.0 \\ vc \\ include \\ xmemory0
Line: 100
线:100
Expression: "(_Ptr_user & (_BIG_ALLOCATION_ALIGNMENT - 1)) == 0" && 0
表达式:“((_ Ptr_user&(_BIG_ALLOCATION_ALIGNMENT-1))== 0” && 0
For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts.
有关程序如何导致断言失败的信息,请参见有关断言的Visual C ++文档。
How can I know what is exactly wrong in my DLL? 我怎么知道DLL中到底有什么问题?
Try changing the C++ function signature to take a WCHAR*
, as C++'s std::string
is incompatible with C#. 尝试将C ++函数签名更改为
WCHAR*
,因为C ++的std::string
与C#不兼容。 Also, to get a handle to the current DLL, use GetModuleHandle(NULL), not LoadLibrary. 另外,要获取当前DLL的句柄,请使用GetModuleHandle(NULL),而不是LoadLibrary。
HINSTANCE hInstance;
__declspec(dllexport) int __cdecl StartDialog(const WCHAR* inString)
{
hInstance = GetModuleHandle(NULL);
DialogBox(hInstance, MAKEINTRESOURCE(ID_DLL_Dialog), NULL, DialogProc);
return 1;
}
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