Telerik.WebControls.RadAjaxManager cause dropw down list not fire handler

I have a front end code look like below

< asp:dropdownlist id="cbo" runat="server" CssClass="combobox" AutoPos开发者_Python百科tBack="True" Width="100%" > < asp:ListItem Selected="True" Value="A">A < asp:ListItem Value="B">B < /asp:dropdownlist>

< rada:RadAjaxManager id="RadAjaxManager1" runat="server"> < AjaxSettings> < rada:AjaxSetting AjaxControlID="cbo"> < UpdatedControls> < rada:AjaxUpdatedControl ControlID="cbo" /> < /UpdatedControls> < /rada:AjaxSetting> < /AjaxSettings> < /rada:RadAjaxManager >

In my code behind, I have the handler for the dropdownlist

Private Sub cbo_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbo.SelectedIndexChanged

textBox1.text = cbo.selectedvalue End Sub

But the drop down do not fire the handler when it is change. When I remove the telerik radajaxmanager, it will fire. Any one have idea why this will happen. Please help.

The handler is probably fired, but to set text in the textbox you have to add its ID (textBox1) in the UpdatedControls collection of the ajax manager setting.