[NTG-context] How to do this in ConTeXt

Hello, I need the format shown below: ------------- |Example 1-1| ----------------------------------------- Here Example 1-1 should be in a black box and text should be in white. The line attached to this box should run up to the right margin. I need a counter for examples to count up and display the example number as shown above for more examples. I am new to ConTeXt. So, I need help. Thanks for your help. Anand