I want to know about update panel with best example

Hi Ashok,

The UpdatePanel control is probably the most important control in the ASP.NET AJAX package. It will AJAX'ify controls contained within it, allowing partial rendering of the area. We already used it in the Hello world example, and in this chapter, we will go in depth with more aspects of the control.

The tag has two childtags - the ContentTemplate and the Triggers tags. The ContentTemplate tag is required, since it holds the content of the panel. The content can be anything that you would normally put on your page, from literal text to web controls. The Triggers tag allows you to define certain triggers which will make the panel update it's content. The following example will show the use of both childtags.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>UpdatePaneltitle>
head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:UpdatePanel runat="server" id="UpdatePanel" updatemode="Conditional">
        <Triggers>
            <asp:AsyncPostBackTrigger controlid="UpdateButton2" eventname="Click" />
        Triggers>
            <ContentTemplate>
                <asp:Label runat="server" id="DateTimeLabel1" />
                <asp:Button runat="server" id="UpdateButton1" onclick="UpdateButton_Click" text="Update" />               
            ContentTemplate>
        asp:UpdatePanel>
        <asp:UpdatePanel runat="server" id="UpdatePanel1" updatemode="Conditional">           
            <ContentTemplate>
                <asp:Label runat="server" id="DateTimeLabel2" />
                <asp:Button runat="server" id="UpdateButton2" onclick="UpdateButton_Click" text="Update" />
            ContentTemplate>
        asp:UpdatePanel>
    form>
body>
html>

Here is the CodeBehind. Just add the following method to the file:

protected void UpdateButton_Click(object sender, EventArgs e)
{
    DateTimeLabel1.Text = DateTime.Now.ToString();
    DateTimeLabel2.Text = DateTime.Now.ToString();

}

So, what's this example all about? Try running it, and click the two buttons. You will notice that then first button updates only the first datestamp, while the second button updates both. Why? We have set the Panels to update conditionally, which means that their content is only updated if something insides them causes a postback, or if one of the defined triggers are fired. As you can see, the first UpdatePanel carries a trigger which references the second button. This will ensure that the first panel is updated even when a control on a different UpdatePanel is used. The AsyncPostBackTrigger tag is pretty simple - it only takes two attributes, the controlid, a reference to the control which can trigger it, and the eventname, which tells which eventtype can cause the trigger to fire.

Please refer the below links

http://msdn.microsoft.com/en-us/library/bb399001.aspx

http://ajax.net-tutorials.com/controls/updatepanel-control/

Thanks

1 Reply

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Satyapriya Nayak14y ago
Hi Ashok,

The UpdatePanel control is probably the most important control in the ASP.NET AJAX package. It will AJAX'ify controls contained within it, allowing partial rendering of the area. We already used it in the Hello world example, and in this chapter, we will go in depth with more aspects of the control.

The
tag has two childtags - the ContentTemplate and the Triggers tags. The ContentTemplate tag is required, since it holds the content of the panel. The content can be anything that you would normally put on your page, from literal text to web controls. The Triggers tag allows you to define certain triggers which will make the panel update it's content. The following example will show the use of both childtags.
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>UpdatePaneltitle>
head>
<body>
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:UpdatePanel runat="server" id="UpdatePanel" updatemode="Conditional">
<Triggers>
<asp:AsyncPostBackTrigger controlid="UpdateButton2" eventname="Click" />
Triggers>
<ContentTemplate>
<asp:Label runat="server" id="DateTimeLabel1" />
<asp:Button runat="server" id="UpdateButton1" onclick="UpdateButton_Click" text="Update" />
ContentTemplate>
asp:UpdatePanel>
<asp:UpdatePanel runat="server" id="UpdatePanel1" updatemode="Conditional">
<ContentTemplate>
<asp:Label runat="server" id="DateTimeLabel2" />
<asp:Button runat="server" id="UpdateButton2" onclick="UpdateButton_Click" text="Update" />
ContentTemplate>
asp:UpdatePanel>
form>
body>
html>
Here is the CodeBehind. Just add the following method to the file:
protected void UpdateButton_Click(object sender, EventArgs e)
{
DateTimeLabel1.Text = DateTime.Now.ToString();
DateTimeLabel2.Text = DateTime.Now.ToString();

}
So, what's this example all about? Try running it, and click the two buttons. You will notice that then first button updates only the first datestamp, while the second button updates both. Why? We have set the Panels to update conditionally, which means that their content is only updated if something insides them causes a postback, or if one of the defined triggers are fired. As you can see, the first UpdatePanel carries a trigger which references the second button. This will ensure that the first panel is updated even when a control on a different UpdatePanel is used. The AsyncPostBackTrigger tag is pretty simple - it only takes two attributes, the controlid, a reference to the control which can trigger it, and the eventname, which tells which eventtype can cause the trigger to fire.

Please refer the below links

http://msdn.microsoft.com/en-us/library/bb399001.aspx

http://ajax.net-tutorials.com/controls/updatepanel-control/

Thanks
0