RadDatePicker Validation Problem

[Sagar]

When I select date less than mindate or type any string value, raddatepicker shows error which is right but if I click on Save button it goes to server side click event.
As I expected it won't go to server side event.& this is not compulsory field so i don't want to use requiredfieldvalidator.

I don't understand,what's the use of Data Input ValidationGroup then?

Here is my code sample -

<telerik:RadDatePicker ID="rdpStartDate" MinDate="1900-01-01" runat="server" Width="200px">
                        <DateInput ID="DateInput1" runat="server" ValidationGroup="SafeVault">
                        </DateInput>
                    </telerik:RadDatePicker>

<asp:Button ID="rbtnSave" runat="server" CausesValidation="true" Text="Save"
                        ValidationGroup="SafeVault" OnClick="btnSave_Click" />

[Shinu]

Hello Sagar,
Hook the the client side event OnClientClick to the Submit Button and cancel the postback accordingly.
Client side:

function Validate()
    {
       var datepickr = $find('<%= rdpStartDate.ClientID %>');
       if (datepickr.get_dateInput()._invalid==false)
       {
           return false;
       }
       return true;
   }

aspx:

<telerik:RadDatePicker ID="rdpStartDate" MinDate="1900-01-01" runat="server" Width="200px">
</telerik:RadDatePicker>
<asp:Button ID="Button2" runat="server" Text="OK"  OnClientClick="if(!Validate()) return false;" OnClick="Button2_Click" />

Thanks,
Shinu.