Text Box Should Accepts only Date using Calendar Extender

Sometimes we need validation for date, that user can only put the date in textbox.

Here is a method through which user can only select the date from calendar extender. User can't type, paste etc. in textbox.

Below is my TextBox along with Calendar Extender.

<asp:TextBox ID="txtDate" runat="server" CssClass="mytextbox" Enabled="False"></asp:TextBox>
         <asp:CalendarExtender ID="txtDate_CalendarExtender" runat="server"
           Enabled="True" TargetControlID="txtDate" Format="dd/MM/yyyy">
         </asp:CalendarExtender>

On the Page_Load event of this form you just need to add a attribute to the TextBox.

protected void Page_Load(object sender, EventArgs e)
   {
        if (!IsPostBack)
        {
            txtDate.Attributes.Add("readonly", "readonly");
        }
   }

Now you can only select date from calendar extender. You can't type, paste etc. in textbox.