In .aspx file
<asp:TextBox ID="TextBoxOrderDate" runat="server" Width="220" MaxLength="10"></asp:TextBox>
<asp:TextBoxWatermarkExtender ID="TextBoxWatermarkExtenderDate" runat="server"
TargetControlID="TextBoxOrderDate" WatermarkText="MM/DD/YYYY">
</asp:TextBoxWatermarkExtender>
Add here css class in WatermarkCssClass property.
<asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="~/calendaricon.png" />
<asp:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="TextBoxOrderDate"
Format="MM/dd/yyyy" PopupButtonID="ImageButton1">
</asp:CalendarExtender>
This compare validator is used to check valid date format.
<asp:CompareValidator ID="CompareValidator2" runat="server" ErrorMessage="Invalid date format."
ValidationGroup="AddRecord" Display="None" ForeColor="Red" ControlToValidate="TextBoxOrderDate"
Operator="DataTypeCheck" Type="Date"></asp:CompareValidator>
This compare validator is used to check future date.
<asp:CompareValidator ID="CompareValidator1" runat="server" ErrorMessage="Date must be less than or equal to the current date." ValidationGroup="AddRecord" Display="None" ForeColor="Red" ControlToValidate="TextBoxOrderDate"
Operator="LessThanEqual" Type="Date"></asp:CompareValidator>
Add validation summary control to display the error message.
<asp:ValidationSummary ID="ValidationSummary1" runat="server" DisplayMode="BulletList"
ShowSummary="false" HeaderText="" ValidationGroup="AddRecord" ShowMessageBox="true" />
Write code in the .cs file
Protected void Page_Load(object sender, EventArgs e){
CompareValidator1.ValueToCompare = DateTime.Now.ToString("MM/dd/yyyy");
}