How to: Display Server Side Custom Validation Messages for ASP.NET Server Controls

You do not have to use the validation control to output a response when the validator or page IsValid property is false. On both the client and server side you can create a custom response, such as a color change in a control or a font change for text on a label.

To display custom validation messages

1. In the Page_Load event handler, call the Validate method of the validation control or of the page.

2. Check the IsValid property of the validation control or page and conditionally add text or a control, or change the properties (for example, color) of a control.

   The following code example displays the text "All entries are valid" when the IsValid property is true, and the text "There are one or more invalid entries" when the property is false.

   If (Me.IsPostBack) Then
       ValidationControl1.Validate()
       If (ValidationControl1.IsValid) Then
           lblOutput.Text = "All entries are valid."
       Else
           lblOutput.Text = "There are one or more invalid entries."
       End If
   End If
   

   if (this.IsPostBack)
     {
         ValidationControl1.Validate();
         if (ValidationControl1.IsValid)
         {
             lblOutput.Text = "All entries are valid.";
         }
         else
         {
             lblOutput.Text = "There are one or more invalid entries.";
         }
     }
   

See Also

Tasks

How to: Control Validation Error Message Display for ASP.NET Server Controls
How to: Format Validation Error Messages for ASP.NET Server Controls

Concepts

Types of Validation for ASP.NET Server Controls
Client-Side Validation for ASP.NET Server Controls

Other Resources

Validation ASP.NET Controls