Hi ajayaj,
Refer below sample.
<div>
<asp:CheckBox ID="chkPassport" runat="server" OnCheckedChanged="CheckedChanged" AutoPostBack="true" />
<asp:TextBox runat="server" ID="txtPassportNumber" />
<asp:RequiredFieldValidator ID="rfvPassportNumber" ErrorMessage="Required" ControlToValidate="txtPassportNumber"
runat="server" Enabled="false" ValidationGroup="o" />
<br />
<asp:Button Text="Submit" runat="server" ValidationGroup="o" OnClick="Submit" />
</div>
C#
protected void CheckedChanged(object sender, EventArgs e)
{
if ((sender as CheckBox).Checked)
{
rfvPassportNumber.Enabled = true;
}
else
{
rfvPassportNumber.Enabled = false;
}
}
protected void Submit(object sender, EventArgs e)
{
if (Page.IsValid)
{
//Do your task.
}
}
VB.Net
Protected Sub CheckedChanged(sender As Object, e As EventArgs)
If TryCast(sender, CheckBox).Checked Then
rfvPassportNumber.Enabled = True
Else
rfvPassportNumber.Enabled = False
End If
End Sub
Protected Sub Submit(sender As Object, e As EventArgs)
'Do your task.
If Page.IsValid Then
End If
End Sub
Screenshot