Button help in ASP.Net/Visual Basic

I am having trouble with the VB side of this:  add another label control that will be toggled back and forth by the use of a button added below it.
The toggle states will be:
1. White foreground with a red background that reads "This is white on red!"
2. Blue foreground with a yellow background that reads "This is blue on yellow!"
 
Any help would be greatly appreciated.  Thanks
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