Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All

Displaying Custom Error Messages for ASP.NET Server Controls

You do not have to use the validation control to output a response when the 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

  • In the Page_Load event handler, call the Validate method, then check the page's IsValid property and conditionally add text or a control, or change the properties (for example, color) of a control. The following example displays the label "All entries are valid" when the IsValid property is true, and "There are one or more invalid entries" when the property is false.
    ' Visual Basic
    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
    
    // C#
    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

Introduction to Validating User Input in Web Forms | Controlling Validation Error Message Display for ASP.NET Server Controls | Formatting Validation Error Messages for ASP.NET Server Controls

Show:
© 2015 Microsoft