win32 - WM_DROPFILES的用法

WM_DROPFILES ： 當用戶將文件拖放到已注冊為丟棄文件的接收者的應用程序窗口中時發送該消息

我們可以利用這個消息獲取文件名稱，並將它們保存到容器里。

LRESULT CALLBACK StaticWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    if (uMsg == WM_DROPFILES)
    {
       HDROP hDrop = reinterpret_cast<HDROP>(wParam);

       // extract files here
       vector<string> files;
       char filename[MAX_PATH];

       UINT count = DragQueryFileA(hDrop, -1, NULL, 0);
       for(UINT i = 0; i < count; ++i)
       {
          if (DragQueryFileA(hDrop, i, filename, MAX_PATH))
              files.push_back(filename);
       }

       DragFinish(hDrop);
       return 0;
    }

    return DefSubclassProc(hwnd, uMsg, wParam, lParam);
}

或者，

LRESULT CALLBACK StaticWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    if (uMsg == WM_DROPFILES)
    {
       HDROP hDrop = reinterpret_cast<HDROP>(wParam);

       // extract files here
       vector<string> files;
       string filename;

       UINT count = DragQueryFileA(hDrop, -1, NULL, 0);
       for(UINT i = 0; i < count; ++i)
       {
          UINT size = DragQueryFileA(hDrop, i, NULL, 0);
          if (size > 0)
          {
              filename.resize(size);
              DragQueryFileA(hDrop, i, &filename[0], size+1);
              files.push_back(filename);
          }
       }

       DragFinish(hDrop);
       return 0;
    }

    return DefSubclassProc(hwnd, uMsg, wParam, lParam);
}