Validation
You can use the built in ASP.NET validation with RadMenu. The menu can trigger validation of other controls on the form when it performs a post-back to the server. Simply set the CausesValidation property to True.
By default, all validators on the Web page must be successful before the postback can occur. You can limit the controls that must be validated when the menu performs a post-back, while still allowing other controls on the Web page to be validated, by using Validation Groups. The validator controls have a ValidationGroup property. The menu also has a ValidationGroup property. The menu only causes validation by those validators whose ValidationGroup property matches the ValidationGroup property of the menu. (The reason the default behavior is for all validators to execute on post-back is because the default value of the ValidationGroup property on both Radmenu and validators is an empty string.)
<telerik:RadMenu RenderMode="Lightweight" runat="server" ID="RadMenu1" Skin="Inox" ValidationGroup="LoginValidationGroup"
CausesValidation="True" OnItemClick="RadMenu1_ItemClick">
<Items>
<telerik:RadMenuItem Text="Products">
<Items>
<telerik:RadMenuItem Text="Missile Systems">
</telerik:RadMenuItem>
<telerik:RadMenuItem Text="Integrated Defense Systems">
</telerik:RadMenuItem>
<telerik:RadMenuItem Text="Space Systems">
</telerik:RadMenuItem>
</Items>
</telerik:RadMenuItem>
<telerik:RadMenuItem Text="My Account">
<Items>
<telerik:RadMenuItem Text="Orders">
</telerik:RadMenuItem>
<telerik:RadMenuItem Text="Profile">
</telerik:RadMenuItem>
</Items>
</telerik:RadMenuItem>
</Items>
</telerik:RadMenu>
<asp:TextBox runat="server" ID="qsfexSearchBox" ValidationGroup="SearchValidationGroup"></asp:TextBox><asp:RequiredFieldValidator
runat="server" CssClass="qsfexErrorMessage" ID="RequiredFieldValidator1" ControlToValidate="qsfexSearchBox"
Display="Dynamic" ErrorMessage="Please enter a search term!" ValidationGroup="SearchValidationGroup" /><asp:LinkButton
runat="server" CssClass="qsfexSearch" CausesValidation="true" ValidationGroup="SearchValidationGroup"></asp:LinkButton>
<p id="qsfexLoginMessage">
Log in to access sections</p>
<fieldset>
<legend>Example Login Form</legend>
<div class="qsfexFieldWrapper">
<asp:Label runat="server" AssociatedControlID="qsfexUsername">Username</asp:Label>
<asp:TextBox runat="server" ID="qsfexUsername"></asp:TextBox>
<asp:RequiredFieldValidator runat="server" CssClass="qsfexErrorMessage" ID="qsfexRequiredFieldValidator1"
ControlToValidate="qsfexUsername" Display="Dynamic" ErrorMessage="Please Fill in Username and Password to see section!"
ValidationGroup="LoginValidationGroup" />
<asp:Label runat="server" AssociatedControlID="qsfexPassword">Password</asp:Label>
<asp:TextBox runat="server" TextMode="password" ID="qsfexPassword"></asp:TextBox>
<asp:RequiredFieldValidator runat="server" CssClass="qsfexErrorMessage" ID="qsfexRequiredFieldValidator2"
ControlToValidate="qsfexPassword" Display="Dynamic" ErrorMessage="Please Fill in Username and Password to see section!"
ValidationGroup="LoginValidationGroup" />
<asp:LinkButton CausesValidation="true" ValidationGroup="LoginValidationGroup" runat="server"
Text="sign in" CssClass="qsfexSignIn">
</asp:LinkButton>
</div>
</fieldset>
For a live example, see Validation Groups.