Problem when displaying the GIF loader via Ajax


I have a below section which is implemented to display loader gif associated to the update panel

  <asp:ScriptManager runat="server"></asp:ScriptManager>
 <asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="updPnlPromotion">
                <img alt="" src="Image/Ajaxloader.gif" />

This is the update panel which contains the dropdown which is a data bound control binded on the radio button checked changed event, but rather than partial postback and the display of loader gif, the entire page posts back.

 <asp:UpdatePanel ID="updPnlPromotion"  runat="server" UpdateMode="Always">
                <td align="left" style="width: 20%;background-color:#CDCD9C">
                    <asp:radiobutton ID="rdbPromotion" runat="server" Text="New Promotion" AutoPostBack="true" GroupName="TacPlan" OnCheckedChanged="rdbPromotion_OnCheckedChanged"  style="font-weight:bold" />
                <td align="left" style="width:30%; vertical-align:middle; background-color:#EBEBEB; text-align:center">
                    <asp:DropDownList runat="server" ID="ddlPromotion" Width="95%"></asp:DropDownList>
                    <asp:Label Text="*" ForeColor="Red" Visible="false" runat="server" ID="lblPromoPlanMandatory"></asp:Label>
                <asp:AsyncPostBackTrigger ControlID="rdbPromotion" EventName="CheckedChanged" />

I don't believe there's an issue with the code you've posted. I created a new ASPX page and copied your code into it. It works as expected (I added a counter to monitor load events):

Here's the code behind I used for testing this:

Public Sub rdbPromotion_OnCheckedChanged(sender As Object, e As EventArgs) Handles rdbPromotion.CheckedChanged
End Sub

Private Sub Default5_Load(sender As Object, e As EventArgs) Handles Me.Load
    Me.counter.Text = Integer.Parse(Me.counter.Text) + 1
End Sub

Seems like a longshot, but maybe the browser you're testing with doesn't support partial rendering, or ASP.NET doesn't think that it does?: