In the following example we will provide you with step by step instructions regarding how to force your user to enter a value inside a text box (he will not be able to continue working without entering this value).The example is a very simple calculator that calculates the square of the number (the number multiplied by itself) entered by the user.Developing robust applications is the target of every serious developer.Being sure from the correctness of the input coming to your application is one of the major practices used to rise application robustness. The process of developing a very simple web application In most of web applications, the user of the application provides input to be manipulated by your web application.
Add required field validators for every textbox and add a validation summary contol.This is a good source of info Startv20/aspnet/doc/validation/second option is to find all textboxes and display the message Required field validators would work great.However, if you prefer a j Query solution you could try something like this. Run(form1) End Sub End Class Public Class Form1 Inherits System. Protected Overloads Overrides Sub Dispose(By Val disposing As Boolean) If disposing Then If Not (components Is Nothing) Then components. Dispose(disposing) End Sub 'Required by the Windows Form Designer Private components As System. IContainer 'NOTE: The following procedure is required by the Windows Form Designer 'It can be modified using the Windows Form Designer. Forms Public Class Main Class Shared Sub Main() Dim form1 As Form = New Form1 Application. Initialize Component() 'Add any initialization after the Initialize Component() call End Sub 'Form overrides dispose to clean up the component list. Possible problem with the Compare Validator checking for a data type of Integer: It seems to just check for the correct digits (0-9), but it doesn't check the range.