使用WM_COPYDATA将结构从C++发送到WPF

Question

我有一个本机C++应用程序,暂时只需要将其命令行字符串和当前鼠标光标坐标发送到WPF应用程序.消息发送和接收都很好,但我无法将IntPtrC#中的实例转换为结构.

当我尝试这样做时,应用程序将无异常崩溃,或者跳过转换它的代码行并接收循环中的下一条消息.这可能意味着发生了原生异常,但我不知道为什么.

这是C++程序.暂时我忽略了命令行字符串并使用伪光标坐标来确保工作正常.

#include "stdafx.h"
#include "StackProxy.h"
#include "string"

typedef std::basic_string<WCHAR, std::char_traits<WCHAR>> wstring;

struct StackRecord
{
    //wchar_t CommandLine[128];
    //LPTSTR CommandLine;
    //wstring CommandLine;
    __int32 CursorX;
    __int32 CursorY;
};

int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
    COPYDATASTRUCT data;
    ZeroMemory(&data, sizeof(COPYDATASTRUCT));

    StackRecord* record = new StackRecord();

    wstring cmdLine(lpCmdLine);
    //record.CommandLine = cmdLine;
    record->CursorX = 5;
    record->CursorY = 16;
    data.dwData = 12;
    data.cbData = sizeof(StackRecord);
    data.lpData = record;

    HWND target = FindWindow(NULL, _T("Window1"));

    if(target != NULL)
    {
        SendMessage(target, WM_COPYDATA, (WPARAM)(HWND) target, (LPARAM)(LPVOID) &data);
    }
    return 0;
}

这是接收消息的WPF应用程序的一部分.IF语句中的第二行被跳过,如果整个事情不只是崩溃.

    public IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        if (msg == Interop.WM_COPYDATA)
        {
            var data = (Interop.CopyDataStruct)Marshal.PtrToStructure(lParam, typeof(Interop.CopyDataStruct));
            var record = (Interop.StackRecord)Marshal.PtrToStructure(data.lpData, typeof(Interop.StackRecord));
            MessageBox.Show(String.Format("X: {0}, Y: {1}", record.CursorX, record.CursorY));
        }
        return IntPtr.Zero;
    }

以下是结构的C#定义.我无休止地玩弄着编组属性,无处可去.

internal static class Interop
{
    public static readonly int WM_COPYDATA = 0x4A;

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct CopyDataStruct
    {
        public IntPtr dwData;
        public int cbData;
        public IntPtr lpData;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 1)]
    public struct StackRecord
    {
        //[MarshalAs(UnmanagedType.ByValTStr)]
        //public String CommandLine;
        public Int32 CursorX;
        public Int32 CursorY;
    }
}

有任何想法吗？

Answer 1

如果没有关于您的设置的更多信息,我不确定您的错误.我尽可能地复制了代码(在WPF应用程序中使用WndProc,从我自己的win32应用程序发送),它对我来说很好.如果运行64位应用程序,有一些错误肯定会出现,即Pack = 1将导致COPYDATASTRUCT未对齐,并且从指针读取可能会很痛苦.

它正在崩溃通过整个？查看传递LPWSTR或wstring的注释代码会导致严重问题,但在解组发送的数据之前,这一点不应该变得明显.

对于它的价值,这是我的代码的片段,似乎对我有用,包括获取命令行.

/* C++ code */
struct StackRecord
{
    wchar_t cmdline[128];
    int CursorX;
    int CursorY;
};

void SendCopyData(HWND hFind)
{
    COPYDATASTRUCT cp;
    StackRecord record;

    record.CursorX = 1;
    record.CursorY = -1;

    _tcscpy(record.cmdline, L"Hello World!");
    cp.cbData = sizeof(record);
    cp.lpData = &record;
    cp.dwData = 12;
    SendMessage(hFind, WM_COPYDATA, NULL, (LPARAM)&cp);
}

/* C# code */
public static readonly int WM_COPYDATA = 0x4A;

[StructLayout(LayoutKind.Sequential)]
public struct CopyDataStruct
{
    public IntPtr dwData;
    public int cbData;
    public IntPtr lpData;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct StackRecord
{
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst=128)]
    public string CommandLine;
    public Int32 CursorX;
    public Int32 CursorY;
}

protected override IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    if (msg == WM_COPYDATA)
    {
        StackRecord record = new StackRecord();
        try
        {
            CopyDataStruct cp = (CopyDataStruct)Marshal.PtrToStructure(lParam, typeof(CopyDataStruct));
            if (cp.cbData == Marshal.SizeOf(record))
            {
                record = (StackRecord)Marshal.PtrToStructure(cp.lpData, typeof(StackRecord));
            }
        }
        catch (Exception e)
        {
            System.Diagnostics.Debug.WriteLine(e.ToString());
        }
        handled = true;
    }
    else
    {
        handled = false;
    }
    return IntPtr.Zero;
}