hi em using telerik radschedular for my fyp i have faced serious problem during working and still i havent fixed it  plz help me  i get inherited edit appointment form of radschedular now i want whenever i click or make new on particular schedular it open that inherited form i used radschedular event handler     

private void radScheduler1_AppointmentEditDialogShowing(object sender, Telerik.WinControls.UI.AppointmentEditDialogShowingEventArgs e)
        {



           Form3 ob = new Form3();
           ob.Show();
        }

form 3 is editappointment form it gives me error when i doubleclick or make schedule on schedular error is "child is not child control of their parent" em beginer on c# plz help me thanks in advance

Code is given below:

   Dim uBl As New UserBusinessLogic()

        Dim _user As IQueryable(Of User) = uBl.GetAllUsersByCompany(_project.Company.CompanyID)

        Dim RadListDataItem1 As RadListDataItem = New RadListDataItem()

        RadListDataItem1.Selected = True

        RadListDataItem1.Text = "Select User"

        RadListDataItem1.Value = "0"

        Me.ddlUsers.DataSource = Nothing

        ddlUsers.Items.Clear()

        Me.ddlUsers.DataSource = _user

        Me.ddlUsers.DisplayMember = "UserName"

        Me.ddlUsers.ValueMember = "UserID"

        Me.ddlUsers.Items.Add(RadListDataItem1)

RadListControl can not transition directly from bound to unbound mode. The data source must be removed first.