How to check for the current background color of a grid?

I'm trying to basically make a toggle button to change the background color of a Windows Phone 7 app.

I'm changing the background color of the Grid named LayoutRoot using this code:

LayoutRoot.Background = new SolidColorBrush(Colors.White);

After I've done that, I want to check the value of LayoutRoot.Background in an if statement (to serve as the toggle). This is where I'm running into problems. I can't seem to come up with a way to check that value.

When I do a LayoutRoot.Background.ToString(), I get System.Windows.Media.SolidBrushColor back as the value. I suppose this makes sense, since the background is a SolidBrushColor. But how do 开发者_开发技巧I get access to the value, so I can check it in my if statement?

You can do:

SolidColorBrush brush = LayoutRoot.Background as SolidColorBrush;
if (brush != null) {
    if (brush.Color == Colors.White) {
        // Do something
    }
}

Other possible brushes include LinearGradientBrush and RadialGradientBrush, so SolidColorBrush is just one of many possible brush types. Which is why there is a if-statement checking for null.