当一个子窗口成为C++桌面应用程序的子窗口时，C# Windows桌面应用程序中会不停地闪烁？

Question

我在C++桌面应用程序中创建了图片控件的父控件，这是我的C#应用程序中一个面板控件的子控件。C++和C#应用程序是在各自的过程中运行的独立应用程序：

Various issues using SetParent to embed window into external process

Embedding HWND into external process using SetParent

我正在使用下面所示的代码来重新养育孩子。C#应用程序启动C++应用程序，将其传递给面板控件的Windows命令行，该命令行应该承载C++应用程序的图片控件。当我运行C#应用程序时，我确实看到了C++图片控件的大纲，它位于指定的C#控件上，该控件是C#应用程序的本机。

不过，我有以下问题：

1) C++和C#应用程序都在闪烁，就像它们每秒钟都被重新绘制很多次一样。

2) C++应用程序中的图片控件通常显示来自我的WebCam的视频提要。I BitBlt()从网络摄像头到C++图片控件的帧。如果没有重新为人父母的话，一切都会好起来，但我根本看不出任何框架。

注意事项：闪烁绝对是引入现在重新父母的子窗口的结果。如果我禁用那个操作，闪烁就不会发生。

有人知道出了什么问题吗?我怎样才能解决呢？下面是C++应用程序中的代码，用于重新养育和将C++主输入线程(拥有图片控件的线程)附加到属于C#应用程序主线程(拥有C#控件的线程)的输入线程：

// The following code executes in the wWinMain() function of the C++
//  app after the main dialog window and it's child controls have been
//  setup and initialized.  The value assigned to g_VideoHostContainerHWnd
//  was passed to the C++ app by the C# app that launched it, as a 
//  command line argument, using the Panel control's Handle property
//  converted to an unsigned integer.
g_OurMainThreadID = GetCurrentThreadId();

if (g_VideoHostContainerHWnd > 0)
{
    // Make our video stream window a parent of the designated window
    //  in the HiveMind client.

    // Get the window handle for the video stream window: IDC_PANEL_PICTURE.
    HWND videoStreamWindow =
        GetDlgItem(
        g_HwndDlg,
        IDC_PANEL_PICTURE);

    if (videoStreamWindow > 0)
    {
        // Get the thread ID for the thread that owns the video host container window.

         g_VideoHostThreadID = GetWindowThreadProcessId(
            g_VideoHostContainerHWnd,
            &g_VideoHostProcessID);

         if (g_VideoHostThreadID > 0)
         {
             // Make the video stream window a child of the HiveMindClient window.
             if (NULL == SetParent(videoStreamWindow, g_VideoHostContainerHWnd))
                 OutputDebugString(L"The reparenting of the video stream window FAILED.");
             else
                 OutputDebugString(L"The reparenting of the video stream window SUCCEEDED.");

             // Attach the our input thread to the thread ID for the process that launched us
             //  (i.e. - owns the video host window).
             if (AttachThreadInput(g_OurMainThreadID, g_VideoHostThreadID, true))
                 OutputDebugString(L"Attaching our input thread to the video host thread SUCCEEDED.");
             else
                 OutputDebugString(L"Attaching our input thread to the video host thread FAILED.");
         }
         else
         {
             OutputDebugString(L"The thread ID of the video host container's owner thread is ZERO.");
         } // else - if (g_VideoHostThreadID > 0)
    }
    else
        OutputDebugString(L"The video stream window handle is INVALID.");
} // if (g_VideoHostContainerHWnd > 0)

Answer 1

我也遇到了这个问题，解决方案是父hwnd需要标志WS_CLIPCHILDREN。