写了一个按钮点击事件测试 点击是发现一个异常 如下图所示:


我的点击事件代码如下(注释掉了窗体加载事件的代码):
private void menuitem_start_Click(object sender, RoutedEventArgs e)
{
ImageBrush imagebrush = new ImageBrush();
imagebrush.ImageSource =new BitmapImage(new Uri("pic/123.png", UriKind.Relative));
grid.Background = imagebrush;
}