设置无窗口边框：

AllowsTransparency="True"

设置窗口可以拖动

增加事件：

wpf之windows设置WindowStyle为None_windows

 处理方法如下：

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            this.MouseDown += delegate { DragMove(); };
        }

设置可以改变大小

   <WindowChrome.WindowChrome>
        <WindowChrome GlassFrameThickness="0" ResizeBorderThickness="4" CaptionHeight="0" CornerRadius="0" />
    </WindowChrome.WindowChrome>

https://docs.microsoft.com/zh-cn/dotnet/api/system.windows.shell.windowchrome?redirectedfrom=MSDN&view=netframework-4.5#%E5%AE%9A%E4%B9%89