Hello!
There is no own custom server validation mechanism in the Ext.Net. But you could use <asp:CustomValidator>.
Example
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<script runat="server">
void Button_Click(object sender, EventArgs e)
{
// Display whether the page passed validation.
if (Page.IsValid)
{
Label1.Text = "Page is valid.";
}
else
{
Label1.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>
<!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 runat="server">
<title>Ext.NET Example</title>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
<ext:Label ID="Label1" runat="server" Text="Enter an even number:" />
<br/>
<ext:TextField ID="TextField1" runat="server" />
<asp:CustomValidator
runat="server"
ControlToValidate="TextField1"
OnServerValidate="ServerValidation"
ErrorMessage="Not an even number!" />
<ext:Button runat="server" Text="Validate" AutoPostBack="true">
<DirectEvents>
<Click OnEvent="Button_Click" />
</DirectEvents>
</ext:Button>
<br/>
</form>
</body>
</html>
Also don't forget there is very flexible mechanism of client side validation in the Ext.Net. If your scenario allows to store data for validation within a page (as Hidden fields) you could use that. If it needs to do some actions on a server you could use DirectMethods from JavaScript validation function.