WPF 下无边框窗体改变大小和移动

紫殿 2014-11-21

展开全文

最近一直在学习 WPF，看着别人做的WPF程序那么漂亮，眼红啊～很多漂亮的程序都是无边框的。于是无边框窗口操作就是最重要的了。无边框窗口的操作一直以来相关的资料就很少。WPF 下的就更少了，有的大多是无边框窗体的移动。在得到群里高人的指点，再查了一些资料之后，终于把问题解决了。

废话不多说，直接来看看如何实现吧!其实现原理很简单：拦截并处理 Windows 消息：WM_NCHITTEST。

WPF 处理 Windows 消息的模式和 WinForm 不一样了。Window 类里没有 WndProc 函数了，想要截取 Windows 消息必须借助 HwndSource 添加 Hook。

[csharp] view plain copy print ?

protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
HwndSource hwndSource = PresentationSource.FromVisual(this) as HwndSource;
if (hwndSource != null)
{
hwndSource.AddHook(new HwndSourceHook(this.WndProc));
}
}
protected virtual IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
return IntPtr.Zero;
}

OK，WndProc 注册完成之后就可以通过 WndProc 函数完成对Windows消息的处理了。可以发现，这里的 WndProc 和标准的 Win32 消息循环很像，只是多了一个 ref bool handled 参数，对于该参数MSDN是这样说明的：指示该消息是否已处理的值。如果该消息已处理，请将值设置为 true；否则请将其设置为 false。在下面我们将会使用到这个参数数。

[csharp] view plain copy print ?

private const int WM_NCHITTEST = 0x0084;
private readonly int agWidth = 12; //拐角宽度
private readonly int bThickness = 4; // 边框宽度
private Point mousePoint = new Point(); //鼠标坐标
protected virtual IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
switch (msg)
{
case WM_NCHITTEST:
this.mousePoint.X = (lParam.ToInt32() &0xFFFF);
this.mousePoint.Y = (lParam.ToInt32() >> 16);
测试鼠标位置#region 测试鼠标位置
// 窗口左上角
if (this.mousePoint.Y - this.Top <= this.agWidth
&& this.mousePoint.X - this.Left <= this.agWidth)
{
handled = true;
return new IntPtr((int)HitTest.HTTOPLEFT);
}
// 窗口左下角
else if (this.ActualHeight + this.Top - this.mousePoint.Y <= this.agWidth
&& this.mousePoint.X - this.Left <= this.agWidth)
{
handled = true;
return new IntPtr((int)HitTest.HTBOTTOMLEFT);
}
// 窗口右上角
else if (this.mousePoint.Y - this.Top <= this.agWidth
&& this.ActualWidth + this.Left - this.mousePoint.X <= this.agWidth)
{
handled = true;
return new IntPtr((int)HitTest.HTTOPRIGHT);
}
// 窗口右下角
else if (this.ActualWidth + this.Left - this.mousePoint.X <= this.agWidth
&& this.ActualHeight + this.Top - this.mousePoint.Y <= this.agWidth)
{
handled = true;
return new IntPtr((int)HitTest.HTBOTTOMRIGHT);
}
// 窗口左侧
else if (this.mousePoint.X - this.Left <= this.bThickness)
{
handled = true;
return new IntPtr((int)HitTest.HTLEFT);
}
// 窗口右侧
else if (this.ActualWidth + this.Left - this.mousePoint.X <= this.bThickness)
{
handled = true;
return new IntPtr((int)HitTest.HTRIGHT);
}
// 窗口上方
else if (this.mousePoint.Y - this.Top <= this.bThickness)
{
handled = true;
return new IntPtr((int)HitTest.HTTOP);
}
// 窗口下方
else if (this.ActualHeight + this.Top - this.mousePoint.Y <= this.bThickness)
{
handled = true;
return new IntPtr((int)HitTest.HTBOTTOM);
}
else // 窗口移动
{
handled = true;
return new IntPtr((int)HitTest.HTCAPTION);
}
#endregion
}
return IntPtr.Zero;
}