I'm building a website using Visual Basic 2008, I need to add server side validation code to the frmPersonnel page.

I'm building a website using Visual Basic 2008, I need to add server side validation code to the frmPersonnel page. Currently, when the Submit button is pressed, the frmPersonnelVerified page is displayed. This is because the frmPersonnelVerified page is set as the Submit button's PostBackUrl property. Instead of having the page go directly to the frmPersonnelVerified page when the Submit button is pressed, I want to do some server side validation. If any of the validation rules fail, we will redisplay the frmPersonnel page with the fields in question highlighted in yellow with an error message displayed. So I need the C# Code to order to do this:to perform server side validation in response to the submit button being clicked. Here are the business rules I want to enforce: Fields may not be empty or filled with spaces. If any field is empty, turn that field background color to yellow and add to/create an error message to be shown in the error label. The end date must be greater than the start date. If the end date is less than the start date, turn both date fields yellow and add to/create an error message to be shown in the error label. If all fields validate properly then the session state items should be set properly and the user should see the frmPersonnelVerified form with all the values displayed