我把一个Form的HWND子类化的this example作为起点,然后在from here的jrohde代码中添加,该代码旨在让你通过点击它上面的任何地方(而不是标题栏)来拖动一个Form。此代码在ReleaseCapture()
line上失败,显示以下消息:E2283 Use . or -> to call '_fastcall TCommonCustomForm::ReleaseCapture()
如果我评论该行代码运行,我可以通过左鼠标移动窗体并拖动,但我不能放过它。鼠标像飞纸一样粘在表格上。如果我用ReleaseCapture()
替换ShowMessage
我可以爆发,但这显然不是要走的路......
我需要做什么让RestoreCapture()
运行?这是Win32应用程序。
以下是我添加到the original开关(uMsg)块的代码:
// two int's defined above the switch statement
static int xClick;
static int yClick;
// new case added to the switch
case WM_LBUTTONDOWN:
SetCapture(hWnd);
xClick = LOWORD(lParam);
yClick = HIWORD(lParam);
break;
case WM_LBUTTONUP:
//ReleaseCapture(); // This is the problem spot <------------------------
ShowMessage("Up");
break;
case WM_MOUSEMOVE:
{
if (GetCapture() == hWnd) //Check if this window has mouse input
{
RECT rcWindow;
GetWindowRect(hWnd,&rcWindow);
int xMouse = LOWORD(lParam);
int yMouse = HIWORD(lParam);
int xWindow = rcWindow.left + xMouse - xClick;
int yWindow = rcWindow.top + yMouse - yClick;
SetWindowPos(hWnd,NULL,xWindow,yWindow,0,0,SWP_NOSIZE|SWP_NOZORDER);
}
break;
谢谢,russ
从错误消息中,您可以推导出编译器将函数ReleaseCapture()解析为TCommonCustomForm :: ReleaseCapture()。但是你想调用Win32 API函数ReleaseCapture()。使用::ReleaseCapture();
而不是ReleaseCapture();
来强制执行此操作。