ASP.Net/Validation by Control/Validation Focus
RequiredFieldValidator on focus leave event (C#)
<source lang="csharp">
<%@ Page Language="C#" %> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server">
<title>Show SetFocusOnError</title>
</head> <body>
<form id="form1" runat="server">
<asp:Label id="lblFirstName" Text="First Name" AssociatedControlID="txtFirstName" Runat="server" />
<asp:TextBox id="txtFirstName" Runat="server" /> <asp:RequiredFieldValidator id="reqFirstName" ControlToValidate="txtFirstName" Text="(Required)" SetFocusOnError="true" Runat="server" />
<asp:Label id="lblLastName" Text="Last Name" AssociatedControlID="txtLastName" Runat="server" />
<asp:TextBox id="txtLastname" Runat="server" /> <asp:RequiredFieldValidator id="reqLastName" ControlToValidate="txtLastName" Text="(Required)" SetFocusOnError="true" Runat="server" />
<asp:Button id="btnSubmit" Text="Submit" Runat="server" />
</form>
</body> </html>
</source>
Validate control on lost focus (C#)
<source lang="csharp">
<%@ Page Language="C#" %> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server">
<title>Show SetFocusOnError</title>
</head> <body>
<form id="form1" runat="server">
<asp:Label id="lblFirstName" Text="First Name" AssociatedControlID="txtFirstName" Runat="server" />
<asp:TextBox id="txtFirstName" Runat="server" /> <asp:RequiredFieldValidator id="reqFirstName" ControlToValidate="txtFirstName" Text="(Required)" SetFocusOnError="true" Runat="server" />
<asp:Label id="lblLastName" Text="Last Name" AssociatedControlID="txtLastName" Runat="server" />
<asp:TextBox id="txtLastname" Runat="server" /> <asp:RequiredFieldValidator id="reqLastName" ControlToValidate="txtLastName" Text="(Required)" SetFocusOnError="true" Runat="server" />
<asp:Button id="btnSubmit" Text="Submit" Runat="server" />
</form>
</body> </html>
</source>