ASP.NET display astrik sign as error using RequiredFieldValidator for required field you need to set ErrorMessage="*" and ToolTip="Password is required." property for RequiredFieldValidator control. The RequiredFieldValidator control belongs to System.Web.UI.WebControls
Syntax
<asp:RequiredFieldValidator ID="rfvPassword" runat="server"
ControlToValidate="txtPassword" ErrorMessage="*" ToolTip="Password is required."></asp:RequiredFieldValidator>
Property | Description |
---|---|
ControlToValidate | Specifies control name which needs to be validate. |
Display | Specifies behavior of the error message. |
EnableClientScript | Specifies whether or not client-side validation is enabled. |
Enabled | Specifies whether or not validation control is enabled or not. |
ErrorMessage | Specifies error messageto be display in validation summary. |
ForeColor | Specifies error message color. |
IsValid | Indicate if associate control passes validation or not. |
SetFocusOnError | Set focus on associate control if validation fails. |
Text | Specifies text to be display if validation fails. |
ValidationGroup | Specifies validation group name. |
Validate | Update the isvalid propery. |
ValidateGetValidationProperty | Determineing validation property of a control, if it exists. |
InitialValue | Specifies initial value of input control. |
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"
Inherits="_Default" %>
<!DOCTYPE html>
<html xmlns="https://www.w3.org/1999/xhtml">
<head runat="server">
<title>ASP.NET Display Astrik for RequiredFieldValidator on client-side Example</title>
</head>
<body>
<form id="Form" runat="server">
<div style="width: 619px">
<asp:Label ID="lblTitle" runat="server" Font-Bold="True" Font-Size="Medium"
Font-Underline="True" Text="ASP.NET Display Astrik for RequiredFieldValidator on client-side Example"></asp:Label>
<br /><br />
<table border="0" width="500px" cellpadding="0" cellspacing="5">
<tr><td>
<asp:Label ID="lblName" runat="server" Font-Bold="True" Font-Size="Small"
Text="User name:"></asp:Label>
</td><td>
<asp:TextBox ID="txtName" runat="server" Height="22px" Width="175px"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvName" runat="server"
ControlToValidate="txtName" ErrorMessage="*" ToolTip="Name is require."></asp:RequiredFieldValidator>
</td></tr>
<tr><td>
<asp:Label ID="lblPassword" runat="server" Font-Bold="True" Font-Size="Small"
Text="Password:"></asp:Label>
</td><td>
<asp:TextBox ID="txtPassword" runat="server" Height="22px" TextMode="Password"
Width="175px"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvPassword" runat="server"
ControlToValidate="txtPassword" ErrorMessage="*" ToolTip="Password is required."></asp:RequiredFieldValidator>
</td></tr>
<tr><td colspan="2">
<asp:Button ID="btnDisabledValidation" runat="server" Font-Bold="True" Text="Submit"
Font-Size="Small" />
</td></tr>
</table>
</div>
</form>
</body>
</html>
Above example will produce following output