将拖拽进行到底 终结篇 WindowsMessage
在 将拖拽进行到底 这篇文中的第四种方法，发一个消息告诉系统鼠标在 CaptionTitle（每个窗口自己 TitleBar）上，这样窗口的拖拽就可以由系统托管了。现在实现了在窗口中任意位置单击鼠标拖拽窗体。这两天，我又发现了一个东东，几乎可以完美的实现这个思想，用 SendMessage(WM_NCLBUTTONDOWN, HTCAPTION, MAKELPARAM( point.x, point.y)) 或者用 UINT CMFCDragDlg::OnNcHitTest(CPoint point) 直接返回 HTCAPTION。SendMessage 的思想是窗口拖拽就直接由系统托管，不管鼠标点击到那里，都告诉系统，鼠标在窗体的 CaptionBar 上―发伪装的消息。用UINT CMFCDragDlg::OnNcHitTest(CPoint point) 的含义是，直接处理系统的 Message，不让系统托管了。在MFC中这两种方法的处理和实现有很多文章在介绍了，这里就不写了。这里就在C#下用类似的方法，来实现SendMessage(WM_NCLBUTTONDOWN, HTCAPTION, MAKELPARAM( point.x, point.y))和 UINT CMFCDragDlg::OnNcHitTest(CPoint point)。
方案 1. SendMessage(WM_NCLBUTTONDOWN, HTCAPTION, MAKELPARAM( point.x, point.y)) Override WndProc 方法当有 WM_LBUTTONDOWN 消息时处理。
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protected override void WndProc(ref Message m)
{
Point screenPoint= Control.MousePosition;
Point clientPoint = this.PointToClient(screenPoint);
if (m.Msg == UnmanagedMethods.WM_LBUTTONDOWN)
{
if(rectangleMin.Contains(clientPoint))
{
this.WindowState = FormWindowState.Minimized;
return;
}
if(rectangleClose.Contains(clientPoint))
{
this.Close();
return;
}
UnmanagedMethods.SendMessage(this.Handle, UnmanagedMethods.WM_NCLBUTTONDOWN, UnmanagedMethods.HTCAPTION, 0);
UnmanagedMethods.MakeLParam(screenPoint.X,clientPoint.Y);
return;
}
base.WndProc (ref m);
}
UnmanagedMethods.SendMessage(this.Handle, UnmanagedMethods.WM_NCLBUTTONDOWN, UnmanagedMethods.HTCAPTION, 0); UnmanagedMethods.MakeLParam(screenPoint.X,clientPoint.Y); return; 发消息告诉系统自己在CaptionBar上。
方案 2. UINT CMFCDragDlg::OnNcHitTest(CPoint point) 自己处理消息，自己修改截获的消息，然后还给系统，告诉系统自己在CaptionBar上。
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protected override void WndProc(ref Message m)
{
Point screenPoint= Control.MousePosition;
Point clientPoint = this.PointToClient(screenPoint);
if (m.Msg == UnmanagedMethods.WM_LBUTTONDOWN)
{
if(rectangleMin.Contains(clientPoint))
{
this.WindowState = FormWindowState.Minimized;
return;
}
if(rectangleClose.Contains(clientPoint))
{
this.Close();
return;
}
m.WParam = new IntPtr(UnmanagedMethods.HTCAPTION);
m.Msg = UnmanagedMethods.WM_NCLBUTTONDOWN;
m.LParam = UnmanagedMethods.MakeLParam(screenPoint.X,clientPoint.Y);
}
base.WndProc (ref m);
}