Click on the Edit button of the Grid View so that it goes into the edit mode.

Note that by default all validation controls validate on the client side.

Right click on the Grid View and select "End template editing" Run the web form.

Let's proceed further by validating on the server side.

We will use the Custom Validator control for this purpose.

On the next step select Customer ID, Company Name, Contact Name and Country columns (Figure 2).

Click on the "Advanced" button and check the "Generate INSERT, UPDATE and DELETE statements" checkbox (Figure 3). Now that you have configured the SQL Data Source control let's bind it with a Grid View control. Open its smart tag and configure it as shown in Figure 4.

You should see an error message as shown in Figure 7.

This way you can attach client side validation controls to the Grid View columns.

You can not attach validation controls directly to these Text Boxes.

We need to convert these Bound Fields to Template Fields.

Next, drag and drop a Required Field Validation control below the Text Box.