Validation

The RadDatePicker control can work seamlessly with standard ASP.NET validation controls. Nevertheless, the validation controls such as RangeValidator and CompareValidator are using a culture-neutral format when comparing the date. For this purpose, we parse the entered date in such culture which format is represented as follow "yyyy-MM-dd-hh-mm-ss" and saving it in RadInputValidationValue client property. When using RangeValidator you need to set its MaximumValue and MinimumValue in such format in order to work correctly. You have to use this format also when using a custom validator. The code snippet below demonstrates how to configure RangeValidator.

<telerik:RadDateInput RenderMode="Lightweight" ID="RadDateInput1" runat="server" DateFormat="d" MinDate="01/01/1990"
    MaxDate="01/01/3000">
</telerik:RadDateInput>
<asp:RangeValidator ID="DateInputRangeValidator" runat="server" ControlToValidate="RadDateInput1"
    ErrorMessage="Choose a date between 5th of January 20015 and 1st of September 20015"
    Display="Dynamic" MaximumValue="20015-09-01-00-00-00" MinimumValue="20015-01-05-00-00-00">
</asp:RangeValidator>

The following example shows a sample period selection page.The user has to enter two dates, the second one being after the first. It uses two RequiredFieldValidator instances to ensure the date pickers are not left empty. A CompareValidator ensures that the second date is greater than the first one.

<table bgcolor="#cccccc">
    <tr>
        <td>Start:</td>
        <td>
            <telerik:RadDatePicker RenderMode="Lightweight" ID="StartDate" MinDate="2008/1/1" runat="server" >
            </telerik:RadDatePicker>
            <asp:RequiredFieldValidator runat="server" ID="validator1"
            ControlToValidate="StartDate"
            ErrorMessage="enter a starting date!">
            </asp:RequiredFieldValidator>
        </td>
    </tr>
    <tr>
        <td>End:</td>
        <td>
            <telerik:RadDatePicker RenderMode="Lightweight" ID="EndDate" MinDate="2008/1/1" runat="server" >
            </telerik:RadDatePicker>
            <asp:RequiredFieldValidator runat="server" ID="validator2"
            ControlToValidate="EndDate"
            ErrorMessage="enter an ending date!">
            </asp:RequiredFieldValidator>
        </td>
    </tr>
    <tr>
        <td></td>
        <td>
            <asp:CompareValidator ID="dateCompareValidator" runat="server"
            ControlToValidate="EndDate"
            ControlToCompare="StartDate"
            Operator="GreaterThan"
            Type="Date"
            ErrorMessage="The end date must be after the start one.">
            </asp:CompareValidator>
        </td>
    </tr>
    <tr>
        <td colspan=2>
            <asp:Button runat="server" Text="Submit" ID="Button1" />
        </td>
    </tr>
</table>    

You need to set the Type property of the CompareValidator to "Date" in order to work with a RadDatePicker. When working with RadTimePicker or RadDateTimePicker control, the property must be set to "String".

For a live example of using validators with a RadDatePicker control, see Date Picker Validation.