Problem on DropDownList on AppointmentTemplate

[shahab]

I want to show some data on AppointmentTemplate which is foreign key. I used this code:

<AppointmentTemplate>
    <div class="rsCustomAppointmentContainer" dir="rtl" style="min-height: 40px; text-align: center;">
        <h2>
            <%# Eval("Subject") %>
        </h2>
        <br />
        <div>
             <telerik:RadComboBox runat="server" ID="DoctorAppointmentRadComboBox" DataTextField="Name"
                DataValueField="Id" Width="97%" Skin="Office2007" Enabled="false" SelectedValue='<%# Eval("DoctorAppointmentId") %>'
                DataSourceID="DoctorAppointmentsEntityDataSource">
            </telerik:RadComboBox>
        </div>
    </div>
</AppointmentTemplate>

and filter Scheduler with another DropDownlist.
But I got " Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control' error. Is there another solution to show value of foreign key.