For this property to return true, all validation server controls in the current validation group must validate successfully. You should check this property only after you have called the Page..::.Validate method, or set the CausesValidation property to true in the OnServerClick event handler for an ASP.NET server control that initiates form processing. These server controls include the Button, HtmlButton, HtmlInputButton, HtmlInputImage, ImageButton, and LinkButton classes.

If you force validation of a validation group using the Validate method, then all validation controls in the specified validation group must validate successfully as well.

The following code example demonstrates using the IsValid property to set up a conditional statement. If the property returns true, the Text property of the lblOutput control is set to "Page is valid!" Otherwise, it is set to "Some of the required fields are empty."

Sub ValidateBtn_Click(sender As Object, e As EventArgs)
    Page.Validate()
    If (Page.IsValid) Then
        lblOutput.Text = "Page is Valid!"
    Else
        lblOutput.Text = "Some required fields are empty."
    End If
End Sub

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

.NET Framework

Reference

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