Change Text when CheckBox is Checked (Selected) in ASP.Net

Hi indradeo,

Please refer below sample code.

HTML Markup

<asp:CheckBox ID="chkValidate" runat="server" OnCheckedChanged="OnCheckedChanged" AutoPostBack="true" />
<asp:Panel ID="pnlValidate" runat="server">
    <asp:Label ID="lblShow" runat="server"></asp:Label>
</asp:Panel>

Code

C#

protected void OnCheckedChanged(object sender, EventArgs e)
{
    if (chkValidate.Checked)
    {
        pnlValidate.Enabled = true;
        lblShow.Text = "TRUE";
    }
    else
    {
        pnlValidate.Enabled = false;
        lblShow.Text = "FALSE";
    }
}

VB.Net

Protected Sub OnCheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
    If chkValidate.Checked Then
        pnlValidate.Enabled = True
        lblShow.Text = "TRUE"
    Else
        pnlValidate.Enabled = False
        lblShow.Text = "FALSE"
    End If
End Sub

Screenshot