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ASP.NET Enable Disable RequiredFieldValidator server side

In order to enable/disable server-side RequiredFieldValidator or validation of the page you need to call "ValidatorEnable" function in Javascript. The RequiredFieldValidator control belongs to System.Web.UI.WebControls

Syntax

public override void Validate()
{
	bool enableValidators = !chkAllow.Checked;
	rfvName.Enabled = enableValidators;
	rfvPassword.Enabled = enableValidators;
	base.Validate();
}

ASP.NET RequiredFieldValidator Control Property

PropertyDescription
ControlToValidateSpecifies control name which needs to be validate.
DisplaySpecifies behavior of the error message.
EnableClientScriptSpecifies whether or not client-side validation is enabled.
EnabledSpecifies whether or not validation control is enabled or not.
ErrorMessageSpecifies error messageto be display in validation summary.
ForeColorSpecifies error message color.
IsValidIndicate if associate control passes validation or not.
SetFocusOnErrorSet focus on associate control if validation fails.
TextSpecifies text to be display if validation fails.
ValidationGroupSpecifies validation group name.
ValidateUpdate the isvalid propery.
ValidateGetValidationPropertyDetermineing validation property of a control, if it exists.
InitialValueSpecifies initial value of input control.

ASP.NET Enable Disable RequiredFieldValidator server side Example - Default.aspx

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" 
Inherits="_Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>ASP.NET Enable Disable RequiredFieldValidator from server-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 Enable/Disable Required Field from server-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" Enabled="false"   
    ControlToValidate="txtName" ErrorMessage="User name can not be empty"></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="Password can not be empty" 
	Enabled="false"></asp:RequiredFieldValidator> 
</td></tr>
<tr><td colspan="2">
<asp:CheckBox ID="chkAllow" runat="server" Text="Allow me without validation"
AutoPostBack="true" oncheckedchanged="chkAllow_CheckedChanged" 
CausesValidation="false" />
</td></tr>

<tr><td colspan="2">
<asp:Button ID="btnDisabledValidation" runat="server" Font-Bold="True" Text="Validate"
Font-Size="Small" onclick="btnDisabledValidation_Click" CausesValidation="false" />
    <asp:Label ID="lblMessage" runat="server" Font-Bold="True" Font-Size="Small" style="color:Red;"   
    Text=""></asp:Label>
</td></tr>
</table>   
</div> 
</form>
</body>
</html>

ASP.NET Enable Disable RequiredFieldValidator server side Example - Default.aspx.cs

using System;
using System.Web.UI;

public partial class _Default : System.Web.UI.Page 
{
    public override void Validate()
    {
        bool enableValidators = !chkAllow.Checked;
        rfvName.Enabled = enableValidators;
        rfvPassword.Enabled = enableValidators;
        base.Validate();
    }
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnDisabledValidation_Click(object sender, EventArgs e)
    {
        Page.Validate();
        if (Page.IsValid)
        {
            lblMessage.Text = "It's valid on server side";
        }
        else
        {
            lblMessage.Text = "It's not valid on server side";
        }
    }
    protected void chkAllow_CheckedChanged(object sender, EventArgs e)
    {
        rfvName.Text = "";
        rfvPassword.Text = "";
    }
}

Above example will produce following output

RequiredFieldValidator

RegularExpressionValidator

RangValidator

CompareValidator

CustomValidator

ValidationSummary