How to retain ViewState while Page Refresh when using UpdatePanel?

qwedster

Folks!

The following is a "Hello World" kind of code for ViewState. I just want to know how to retain the ViewState 1) while Page Refresh when using UpdatePanel and also 2) While I reverting back to the page after round trip when using UpdatePanel?

In the following code snippet the ViewState is killed when I click page refresh or when I go some page and revert back

Code Snippet:

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// Default.aspx:
 
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="ASPCS2008ViewState._Default" 

EnableViewState="true" ViewStateEncryptionMode="Always" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<script runat="server">
 
    private int Counter

    {

        get

        {

            object Instance = ViewState["Counter"];

            return (Instance == null) ? 0 : (int)Instance;

        }

        set

        {

            ViewState["Counter"] = value;

        }

    }
 
    protected void Button1_Click(object sender, EventArgs e)

    {

        Counter++;

        TextBox1.Text = Counter.ToString();

    }
 
    protected void Button2_Click(object sender, EventArgs e)

    {

        Response.Redirect("SomePage.aspx");

    }  
 
</script>
 
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">

    <title></title>

</head>

<body>

    <form id="form1" runat="server" >

    <asp:ScriptManager ID="ScriptManager1" runat="server" />

    <asp:UpdatePanel ID="UpdatePanel1" runat="server" >

    <ContentTemplate>
 
    <div>
 
        <asp:Button ID="Button1" runat="server" Text="Click" onclick="Button1_Click" />

        <br />

        <br />

        <span lang="en-us">

        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

        <br />

        </span>

        <br />

        <asp:Button ID="Button2" runat="server" Text="Go Some Page" 

            onclick="Button2_Click" />

        <br />

        <br />
 
    </div>
 
     </ContentTemplate>

     </asp:UpdatePanel>

    </form>

</body>

</html>
 
// SomePage.aspx
 
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="SomePage.aspx.cs" Inherits="ASPCS2008ViewState.SomePage" 

EnableViewState="true" ViewStateEncryptionMode="Always" %>
 
<!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 Button2_Click(object sender, EventArgs e)

    {

        Response.Redirect("Default.aspx");

    }

</script>
 
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">

    <title></title>

</head>

<body>

    <form id="form1" runat="server">
 
    <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>

    <asp:UpdatePanel ID="UpdatePanel1" runat="server" >

    <ContentTemplate>

    <p>

        <span lang="en-us">Wellcome to Some Page! </span>

    </p>
 
    <p>

    <asp:Button ID="Button2" runat="server" Text="Go back" onclick="Button2_Click" />

    </p>

    <div>
 
    </div>
 
    </ContentTemplate>

    </asp:UpdatePanel>

    </form>

</body>

</html>

Thanks

Frinavale

The Refresh button?
Like the browser refresh button? Or is one of your buttons a "refresh button".

If you're talking about the web-browser's refresh button then this is expected behaviour....

The web browser makes a request for the page
The initial web page is sent to the browser
You do a bunch of asynchronous requests to the server and your counter is changed
Now you hit the refresh button....the refresh button preforms the last "full page request" to the server which means that it loads the initial page again.

-Frinny

qwedster

Thanks for the reply!

How to retain ViewState while Page Refresh when using UpdatePanel?

✓ answered by Frinavale

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