Databind the result of a method call. runat="server" ControlToValidate="theInput" ErrorMessage="input is required" /> runat="server" ControlToValidate="theInput" ErrorMessage="input must be >= 0 and < 20" Type="integer" MinimumValue="0" MaximumValue="20" /> runat="server" type="submit" Text="Calculate Factorial" />The result is: <%# CalculateFactorial(Int32.Parse(theInput.Text)).ToString() %>