[C# net 4] Load page please wait (not updating but page load)

Hi all, hope in your help and suggestions.

I need show the classic message 'Please wait' when my gridview is populated in my page aspx.

In the google search I find all examples and tutorials with buttons that update the page aspx, e.g.:
http://aspsnippets.com/Articles/Display-loading-progress-image-when-Page-Loads-or-does-PostBack-using-ASPNet.aspx

In this demo when call gridview.aspx the message not show, instead is show when click in the button 'btnSubmit'.

Can you help me?

I tried this version but the images spinner4-greenie.gif not showed:








AutoGenerateColumns="False" PageSize="13" ShowHeader="true" OnPageIndexChanging="GridView1_PageIndexChanging"
OnRowDataBound="GridView1_RowDataBound" CssClass="mGrid" ShowHeaderWhenEmpty="true"
EmptyDataText="No data available." DataKeyNames="ID" OnRowEditing="GridView1_RowEditing"
OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowCommand="GridView1_RowCommand"
OnRowUpdating="GridView1_RowUpdating" OnRowDeleting="GridView1_RowDeleting">

...