Adding a Delay to the Sample Application
If your application updates each page of data quickly, you might not see the content of the UpdateProgress control on the page. The UpdateProgress control supports a DisplayAfter property that enables you to set a delay before the control is displayed. This prevents the control from flashing in the browser if the update occurs very fast. By default, the delay is set to 500 milliseconds (.5 second), meaning that the UpdateProgress control will not be displayed if the update takes less than half a second.
In a development environment, you can add an artificial delay to your application to make sure that the UpdateProgress control is functioning as intended. This is an optional step and is only for testing your application.
To add a delay to the sample application
Inside the UpdatePanel control, select the GridView control.
In the Properties window, click the Events button.
Double-click the PageIndexChanged event to create an event handler.
Add the following code to the PageIndexChanged event handler to artificially create a three-second delay:
'Include three second delay for example only.
System.Threading.Thread.Sleep(3000)
//Include three second delay for example only.
System.Threading.Thread.Sleep(3000);
.gif) Note: |
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The handler for the
PageIndexChanged event intentionally introduces a delay for this tutorial. In practice, you would not introduce a delay. Instead, the delay would be the result of server traffic or of server code that takes a long time to process, such as a long-running database query.
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Save your changes, and then press CTRL+F5 to view the page in a browser.
Because there is now a three-second delay every time that you move to a new page of data, you will be able to see the UpdateProgress control.
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub GridView1_PageIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)
'Include three second delay for example only.
System.Threading.Thread.Sleep(3000)
End Sub
</script>
<html >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
</div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:GridView ID="GridView1" runat="server" AllowPaging="True" CellPadding="4" DataSourceID="SqlDataSource1"
ForeColor="#333333" GridLines="None" OnPageIndexChanged="GridView1_PageIndexChanged">
<FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
<SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
<PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
<HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:AdventureWorksConnectionString %>"
SelectCommand="SELECT FirstName, LastName FROM HumanResources.vEmployee ORDER BY LastName, FirstName">
</asp:SqlDataSource>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
Getting employees...
</ProgressTemplate>
</asp:UpdateProgress>
</form>
</body>
</html>
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void GridView1_PageIndexChanged(object sender, EventArgs e)
{
//Include three second delay for example only.
System.Threading.Thread.Sleep(3000);
}
</script>
<html >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
</div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:GridView ID="GridView1" runat="server" AllowPaging="True" CellPadding="4" DataSourceID="SqlDataSource1"
ForeColor="#333333" GridLines="None" OnPageIndexChanged="GridView1_PageIndexChanged">
<FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
<SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
<PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
<HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:AdventureWorksConnectionString %>"
SelectCommand="SELECT FirstName, LastName FROM HumanResources.vEmployee ORDER BY LastName, FirstName">
</asp:SqlDataSource>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
Getting employees...
</ProgressTemplate>
</asp:UpdateProgress>
</form>
</body>
</html>