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.

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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.