asp.net validation to make sure textbox has integer values

Question

I have a required validation setup on a textbox, but I also have to make sure it is an integer.

How can I do this?

Answer 1

If all that you are concerned about is that the field contains an integer (i.e., not concerned with a range), then add a CompareValidator with it's Operator property set to DataTypeCheck:

<asp:CompareValidator runat="server" Operator="DataTypeCheck" Type="Integer"   ControlToValidate="ValueTextBox" ErrorMessage="Value must be a whole number" /> 

If there is a specific range of values that are valid (there probably are), then you can use a RangeValidator, like so:

<asp:RangeValidator runat="server" Type="Integer"  MinimumValue="0" MaximumValue="400" ControlToValidate="ValueTextBox"  ErrorMessage="Value must be a whole number between 0 and 400" /> 

These will only validate if there is text in the TextBox, so you will need to keep the RequiredFieldValidator there, too.

As @Mahin said, make sure you check the Page.IsValid property on the server side, otherwise the validator only works for users with JavaScript enabled.