小编Him*_*pai的帖子

我点击按钮的边框背景是蓝色的，一秒钟后它应该是红色的。它是红色但不是蓝色。为什么？

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Border Width="111" Name="op" Height="111">
        <Button Name="opbtn" Click="opbtn_Click" Width="50" Height="23">click</Button>
    </Border>
</Window>

代码隐藏：

private void opbtn_Click(object sender, RoutedEventArgs e)
{
    op.BorderBrush = System.Windows.Media.Brushes.Blue;
    DateTime obj1 = new DateTime(); 
    DateTime obj2 = DateTime.Now.AddMilliseconds(200);
    while (obj2 > obj1)
    {
        obj1 = DateTime.Now;
    }
    op.BorderBrush = System.Windows.Media.Brushes.Red;
}