PostMessage的字节数组编组

Question

我正在尝试将一些C++代码移植到C#,我需要做的一件事就是PostMessage将一个字节数组传递给另一个进程的窗口.我正在尝试将源代码提供给另一个程序,以便我可以确切地看到它的期望,但与此同时,这是原始C++代码的样子:

unsigned long result[5] = {0};
//Put some data in the array
unsigned int res = result[0];
Text winName = "window name";
HWND hWnd = FindWindow(winName.getConstPtr(), NULL);
BOOL result = PostMessage(hWnd, WM_COMMAND, 10, res);

这就是我现在拥有的:

[DllImport("User32.dll", SetLastError = true, EntryPoint = "FindWindow")]
public static extern IntPtr FindWindow(String lpClassName, String lpWindowName);

[DllImport("User32.dll", SetLastError = true, EntryPoint = "SendMessage")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, ref COPYDATASTRUCT lParam);

[StructLayout(LayoutKind.Sequential)]
public struct COPYDATASTRUCT
{
    public int dwData;
    public int cbData;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst=32)]
    public byte[] lpData;
}

public const int WM_COPYDATA = 0x4A;

public static int sendWindowsByteMessage(IntPtr hWnd, int wParam, byte[] data)
{
    int result = 0;

    if (hWnd != IntPtr.Zero)
    {
        int len = data.Length;
        COPYDATASTRUCT cds;
        cds.dwData = wParam;
        cds.lpData = data;
        cds.cbData = len;
        result = SendMessage(hWnd, WM_COPYDATA, wParam, ref cds);
    }

    return result;
}

//*****//

IntPtr hWnd = MessageHelper.FindWindow(null, windowName);
if (hWnd != IntPtr.Zero)
{
    int result = MessageHelper.sendWindowsByteMessage(hWnd, wParam, lParam);
    if (result == 0)
    {
        int errCode = Marshal.GetLastWin32Error();
    }
}

请注意,我必须从使用PostMessageC++ 切换到SendMessageC#.

所以现在发生的是我得到的结果和errCode都是0,我相信这意味着消息没有被处理 - 实际上看着另一个应用程序,我没有看到预期的响应.我已经验证了hWnd != IntPtr.Zero,所以我认为消息被发布到正确的窗口,但消息数据是错误的.我有什么想法我做错了吗？

更新

在评论中尝试这些建议后,我仍然没有运气.这是我目前得到的:

[DllImport("User32.dll", SetLastError = true)]
public static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

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

public struct BYTEARRDATA
{
    public byte[] data;
}

public static IntPtr IntPtrAlloc<T>(T param)
{
    IntPtr retval = Marshal.AllocHGlobal(Marshal.SizeOf(param));
    Marshal.StructureToPtr(param, retval, false);
    return (retval);
}

public static void IntPtrFree(IntPtr preAllocated)
{
    //Ignores errors if preAllocated is IntPtr.Zero!
    if (IntPtr.Zero != preAllocated)
    {
        Marshal.FreeHGlobal(preAllocated); 
        preAllocated = IntPtr.Zero;
    }
}

BYTEARRDATA d;
d.data = data;
IntPtr buffer = IntPtrAlloc(d);

COPYDATASTRUCT cds;
cds.dwData = new IntPtr(wParam);
cds.lpData = buffer;
cds.cbData = Marshal.SizeOf(d);

IntPtr copyDataBuff = IntPtrAlloc(cds);
IntPtr r = SendMessage(hWnd, WM_COPYDATA, IntPtr.Zero, copyDataBuff);
if (r != IntPtr.Zero)
{
    result = r.ToInt32();
}

IntPtrFree(copyDataBuff);
copyDataBuff = IntPtr.Zero;
IntPtrFree(buffer);
buffer = IntPtr.Zero;

这是一个试图联系32位进程的64位进程,所以可能有一些东西,但我不确定是什么.

Answer 1

问题是COPYDATASTRUCT应该包含一个指针作为最后一个成员,并且你传递整个数组.

看看pinvoke.net上的例子:http://www.pinvoke.net/default.aspx/Structures/COPYDATASTRUCT.html

评论后的更多信息:

鉴于这些定义:

const int WM_COPYDATA = 0x004A;

[StructLayout(LayoutKind.Sequential)]
struct COPYDATASTRUCT
{
    public IntPtr dwData;
    public int cbData;
    public IntPtr lpData;
}
[DllImport("User32.dll", SetLastError = true, EntryPoint = "FindWindow")]
public static extern IntPtr FindWindow(String lpClassName, String lpWindowName);

[DllImport("User32.dll", SetLastError = true, EntryPoint = "SendMessage")]
public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, ref COPYDATASTRUCT lParam);

我可以创建两个.NET程序来测试WM_COPYDATA.这是接收器的窗口过程:

protected override void WndProc(ref Message m)
{
    switch (m.Msg)
    {
        case WM_COPYDATA:
            label3.Text = "WM_COPYDATA received!";
            COPYDATASTRUCT cds = (COPYDATASTRUCT)Marshal.PtrToStructure(m.LParam, typeof(COPYDATASTRUCT)); 
            byte[] buff = new byte[cds.cbData];
            Marshal.Copy(cds.lpData, buff, 0, cds.cbData);
            string msg = Encoding.ASCII.GetString(buff, 0, cds.cbData);
            label4.Text = msg;
            m.Result = (IntPtr)1234;
            return;
    }
    base.WndProc(ref m);
}

以及使用它调用它的代码SendMessage:

Console.WriteLine("{0} bit process.", (IntPtr.Size == 4) ? "32" : "64");
Console.Write("Press ENTER to run test.");
Console.ReadLine();
IntPtr hwnd = FindWindow(null, "JimsForm");
Console.WriteLine("hwnd = {0:X}", hwnd.ToInt64());
var cds = new COPYDATASTRUCT();
byte[] buff = Encoding.ASCII.GetBytes(TestMessage);
cds.dwData = (IntPtr)42;
cds.lpData = Marshal.AllocHGlobal(buff.Length);
Marshal.Copy(buff, 0, cds.lpData, buff.Length);
cds.cbData = buff.Length;
var ret = SendMessage(hwnd, WM_COPYDATA, 0, ref cds);
Console.WriteLine("Return value is {0}", ret);
Marshal.FreeHGlobal(cds.lpData);

当发送方和接收方都是32位进程并且它们是64位进程时,这可以正常工作.如果两个进程的"位数"不匹配,它将无法工作.

有几个原因导致这种情况不适用于32/64或64/32.想象一下,您的64位程序想要将此消息发送到32位程序.lParam64位程序传递的值将长达8个字节.但32位程序只能看到它的4个字节.所以该程序将不知道从何处获取数据!

即使这样有效,COPYDATASTRUCT结构的大小也不同.在32位程序中,它包含两个指针和一个DWORD,总大小为12个字节.在64位程序中,COPYDATASTRUCT长度为20个字节:两个指针,每个指针8个字节,长度为4个字节.

从另一个角度来看,你也有类似的问题.

我严重怀疑你会WM_COPYDATA为32/64或64/32工作.