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Categories / ASP.Net Tutorial / Validation
 

Using the CustomValidator control to perform server-side validations (C#)

<%@ Page Language="C#" %> <script runat="server">     protected void Button1_Click(Object sender, EventArgs e) {          if (Page.IsValid) {             Label1.Text = "VALID ENTRY!";          }     }     void ValidateNumber(object source, ServerValidateEventArgs args)     {        try         {           int num = int.Parse(args.Value);           args.IsValid = ((num%5) == 0);        }        catch(Exception ex)        {           args.IsValid = false;        }     } </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server">     <title>CustomValidator</title> </head> <body>     <form id="form1" runat="server">     <div>                      Number:              <asp:TextBox ID="TextBox1"               Runat="server"></asp:TextBox>              &nbsp;             <asp:CustomValidator ID="CustomValidator1"               Runat="server" ControlToValidate="TextBox1"               ErrorMessage="Number must be divisible by 5"               OnServerValidate="ValidateNumber"></asp:CustomValidator>                      <asp:Button ID="Button1" OnClick="Button1_Click"               Runat="server" Text="Button"></asp:Button>                      <asp:Label ID="Label1" Runat="server"></asp:Label>              </div>     </form> </body> </html>