How To Validate A ListBox Control In Asp.net to make sure it has items listed in it.

I have two listboxes on an asp.net page. The first one is a multiselect that allows the user to select specific employees.  They can then move their selected employees (via a button click) to the other listbox.  Pretty standard fare and that all works fine.   Before they click continue, I want to make sure there are employees in the second listbox and it is not empty.  How would I validate that?  Can I use a required field validator somehow or would I need a custom validator?  Please be specific.

Thanks in advance
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kenadelglassAsked:
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dkloeckCommented:
following code should do it:


if(listBox.Items.Count != 0)
   //continue

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kenadelglassAuthor Commented:
dkloeck - I know I can do that on the button click but I would like to use the validation controls for this - Do I need to use a custom validator then or is there a way to do it with the Required field validator?
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kenadelglassAuthor Commented:
It works fine. I decided to enable and disable the Continue button based on the lstBox.Items.Count rather than use the Validators.  Thanks
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dkloeckCommented:
See http://www.devhood.com/Tutorials/tutorial_details.aspx?tutorial_id=46 for more info on validators, if you want to try out the other way sometime
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