当窗口失焦时，WndProc 不起作用答案

【问题标题】：WndProc does not work when window is out of focus当窗口失焦时，WndProc 不起作用
【发布时间】：2019-07-19 07:56:28
【问题描述】：

我想将SendMessage 用于来自全局挂钩dll 的WM_COPYDATA，然后将其发送到myMainwindow WndProc。 WndProc只在活动屏时监听procs，在失焦时不接收dll发送的消息。

这是 WndProc 的限制吗？有没有更好的替代品？

【问题讨论】：

WM_COPYMESSAGE 是来自 Windows 11 的一种新消息吗？
我的错，我想说的是 WM_COPYDATA

标签： c# sendmessage wndproc

【解决方案1】：

我发现问题出在我的SendMessage 通话中使用的HWND。它必须由所有 dll 共享，如下所示：

#pragma data_seg("Shared")
//our hook handle which will be returned by calling SetWindowsHookEx function
HHOOK hkKey = NULL;
HINSTANCE hInstHookDll = NULL;  //our global variable to store the instance of our DLL
HWND pHWnd = NULL; // global variable to store the mainwindow handle
#pragma data_seg() //end of our data segment

#pragma comment(linker,"/section:Shared,rws")
// Tell the compiler that Shared section can be read,write and shared

__declspec(dllexport) LRESULT CALLBACK procCharMsg(int nCode, WPARAM wParam, LPARAM lParam)
//this is the hook procedure
{
    //a pointer to hold the MSG structure that is passed as lParam
    MSG* msg;
    //to hold the character passed in the MSG structure's wParam
    char charCode;
    if (nCode >= 0 && nCode == HC_ACTION)
        //if nCode is less than 0 or nCode
        //is not HC_ACTION we will call CallNextHookEx
    {
        //lParam contains pointer to MSG structure.
        msg = (MSG*)lParam;
        if (msg->message == WM_CHAR)
            //we handle only WM_CHAR messages
        {
            SendMessage(pHWnd, WM_CHAR, (WPARAM)msg->message, (LPARAM)0); // This should now work globally
        }
    }
    return CallNextHookEx(hkKey, nCode, wParam, lParam);
}

// called by main app to establish a pointer of itself to the dlls
extern "C" __declspec(dllexport) int SetParentHandle(HWND hWnd) {
    pHWnd = hWnd;
    if (pHWnd == NULL) {
        return 0;
    }

    return 1;
}

我应该将我的代码连同问题一起发布，因为小事情总是很难单独发现。

【讨论】：