首先将WindowStyle样式设置为none，AllowTransParency为True，BackGround为Transparent，OpacityMask为White
WindowStyle="None" Background="Transparent" OpacityMask="White" AllowsTransparency="True" ResizeMode="NoResize"
其次将grid加一个boder，方便加圆角就可以了
<Border Background="White" Height="192" Width="169" BorderThickness="1" BorderBrush="red" CornerRadius="4,4,4,4" Name="top">
<Border.Effect>
<DropShadowEffect ShadowDepth="0" Color="White" BlurRadius="4"/>
</Border.Effect>
<Label Margin="50,50,0,0">窗体圆角</Label>
</Border>
效果图：