我有一个Win32 HWND,想要允许用户按住Ctrl键和鼠标左键来拖动窗口到屏幕上的其他位置。已知(1)我可以检测到用户按住Ctrl键、鼠标左键并移动鼠标的操作,和(2)新旧鼠标位置,如何使用Win32 API和我的HWND来改变窗口的位置?
实现一个WM_NCHITTEST消息处理程序。调用DefWindowProc(),并检查返回值是否为HTCLIENT。如果是,则返回HTCAPTION,否则返回DefWindowProc的返回值。现在可以单击客户区域并拖动窗口,就像通过单击标题栏拖动窗口一样。
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_NCHITTEST: {
LRESULT hit = DefWindowProc(hWnd, message, wParam, lParam);
if (hit == HTCLIENT) hit = HTCAPTION;
return hit;
}
// etc..
}
bool mousedown = false;
POINT lastLocation;
bool mousedown表示用户是否按住鼠标左键
然后在回调函数中,您需要编写以下几行代码:
case WM_LBUTTONDOWN: {
mousedown = true;
GetCursorPos(&lastLocation);
RECT rect;
GetWindowRect(hwnd, &rect);
lastLocation.x = lastLocation.x - rect.left;
lastLocation.y = lastLocation.y - rect.top;
break;
}
case WM_LBUTTONUP: {
mousedown = false;
break;
}
case WM_MOUSEMOVE: {
if (mousedown) {
POINT currentpos;
GetCursorPos(¤tpos);
int x = currentpos.x - lastLocation.x;
int y = currentpos.y - lastLocation.y;
MoveWindow(hwnd, x, y, window_lenght, window_height, false);
}
break;
}