ServerValidateEventArgs.IsValid Property     
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets whether the value specified by the Value property passed validation.
public:
 property bool IsValid { bool get(); void set(bool value); };public bool IsValid { get; set; }member this.IsValid : bool with get, setPublic Property IsValid As BooleanProperty Value
true to indicate that the value specified by the Value property passed validation; otherwise, false.
Examples
The following example demonstrates how to use the IsValid property to store the results of the validation.
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>CustomValidator ServerValidate Example</title>
<script runat="server">
      void ValidateBtn_OnClick(object sender, EventArgs e) 
      { 
         // Display whether the page passed validation.
         if (Page.IsValid) 
         {
            Message.Text = "Page is valid.";
         }
         else 
         {
            Message.Text = "Page is not valid!";
         }
      }
      void ServerValidation(object source, ServerValidateEventArgs args)
      {
         try 
         {
            // Test whether the value entered into the text box is even.
            int i = int.Parse(args.Value);
            args.IsValid = ((i%2) == 0);
         }
         catch(Exception ex)
         {
            args.IsValid = false;
         }
      }
   </script>    
</head>
<body>
   <form id="form1" runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>
      <asp:Label id="Message"  
           Text="Enter an even number:" 
           Font-Names="Verdana" 
           Font-Size="10pt" 
           runat="server"
           AssociatedControlID="Text1"/>
      <br />
      <asp:TextBox id="Text1" 
           runat="server" />
    
        
      <asp:CustomValidator id="CustomValidator1"
           ControlToValidate="Text1"
           Display="Static"
           ErrorMessage="Not an even number!"
           ForeColor="green"
           Font-Names="verdana" 
           Font-Size="10pt"
           OnServerValidate="ServerValidation"
           runat="server"/>
      <br />
 
      <asp:Button id="Button1"
           Text="Validate" 
           OnClick="ValidateBtn_OnClick" 
           runat="server"/>
   </form>
  
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>CustomValidator ServerValidate Example</title>
<script runat="server">
      Sub ValidateBtn_OnClick(sender As Object, e As EventArgs) 
         ' Display whether the page passed validation.
         If Page.IsValid Then 
            Message.Text = "Page is valid."
         Else 
            Message.Text = "Page is not valid!"
         End If
      End Sub
      Sub ServerValidation(source As Object, args As ServerValidateEventArgs)
         Try 
            ' Test whether the value entered into the text box is even.
            Dim num As Integer = Integer.Parse(args.Value)
            args.IsValid = ((num mod 2) = 0)
 
         Catch ex As Exception
         
            args.IsValid = false
         End Try
      End Sub
   </script>    
</head>
<body>
   <form id="form1" runat="server">
  
      <h3>CustomValidator ServerValidate Example</h3>
      <asp:Label id="Message"
           Text="Enter an even number:" 
           Font-Names="Verdana" 
           Font-Size="10pt" 
           runat="server"
           AssociatedControlID="Text1" />
      <br />
      <asp:TextBox id="Text1" 
           runat="server" />
    
        
      <asp:CustomValidator id="CustomValidator1"
           ControlToValidate="Text1"
           Display="Static"
           ErrorMessage="Not an even number!"
           ForeColor="green"
           Font-Names="verdana" 
           Font-Size="10pt"
           OnServerValidate="ServerValidation"
           runat="server"/>
      <br />
 
      <asp:Button id="Button1"
           Text="Validate" 
           OnClick="ValidateBtn_OnClick" 
           runat="server"/>
   </form>
  
</body>
</html>
Remarks
Once your validation routine finishes, use the IsValid property to indicate whether the value specified by the Value property passed validation. This value determines whether the input control associated with the CustomValidator control passed validation.