Before looking at the code, Read about – What is JumpStart?
<%@ Page Language="C#" EnableViewState="true"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
/* ViewStateMode -
* 1) It is a new feature in ASP.Net 4.0. Using this we have explicit control on the controls
* which participate in viewstate, thereby preventing unnecessary information going into
* viewstate during postbacks.
* 2) In previous versions of ASP.Net, you can disabled viewstate for complete page by setting
* EnableViewState="false" in @Page directive, the same can be used in ASP.Net 4.0, but for
* more robost control on viewstate we got to use ViewStateMode.
* 3) Once we disable viewstate for complete page using EnableViewState, we cannot enable it for
* any other control used in that page, but using ViewStateMode you can achieve the same.
* 4) You can disable viewstate of the page by setting ViewStateMode="Disabled", and still you can
* enable viewstate for child controls using theie ViewStateMode="Enabled".
* 5) ViewStateMode can have three values - Enabled, Disabled, Inherit. First two values are self
* explanatory, Inherit means the control will inherit its ViewStateMode from its container.
* 6) The default ViewStateMode of Page is Enabled and for that of a control is Inherit.
* 7) ViewStateMode can be used in @Page directive too.
* 
One must be careful in implementing this feature, as it may result unwanted results if it is
* not used in appropriate ways.
*/
protected void Page_Load(object sender, EventArgs e)
{
Page.ViewStateMode = System.Web.UI.ViewStateMode.Disabled;
if (!IsPostBack)
{
Label1.Text = "John";
Label2.Text = "Chris";
Label3.Text = "Bob";
Label4.Text = "Adam";
Label5.Text = "Scott";
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<!-- Label Will not hold its value after postback -->
<asp:Label ID="Label1" ViewStateMode="Disabled" runat="server" Text="Label1"></asp:Label>
<!-- Label Will hold its value after postback -->
<asp:Label ID="Label2" ViewStateMode="Enabled" runat="server" Text="Label2"></asp:Label>
<!-- Label Will not hold its value after postback, as its container's viewstate is disabled -->
<asp:PlaceHolder ID="PlaceHolder1" ViewStateMode="Disabled" runat="server">
<asp:Label ID="Label3" ViewStateMode="Inherit" runat="server" Text="Label3"></asp:Label>
</asp:PlaceHolder>
<!-- Label Will hold its value after postback, as its container's viewstate is Enabled -->
<asp:PlaceHolder ID="PlaceHolder2" ViewStateMode="Enabled" runat="server">
<asp:Label ID="Label4" ViewStateMode="Inherit" runat="server" Text="Label4"></asp:Label>
</asp:PlaceHolder>
<!-- Label Will hold its value after postback, even though its container's viewstate is
disabled, as label's viewstate in enabled -->
<asp:PlaceHolder ID="PlaceHolder3" ViewStateMode="Disabled" runat="server">
<asp:Label ID="Label5" ViewStateMode="Enabled" runat="server" Text="Label5"></asp:Label>
</asp:PlaceHolder>
<asp:Button ID="Button1" runat="server" Text="PostBack" />
</div>
</form>
</body>
</html>
OUTPUT –
Before Postback - After PostBack –
Use the below form to express your comments, views and suggestions about the article. I request everyone who leaves a comment to be more specific to this article.
Please note that all irrelevant comments are moderated. And in case of any comments having abusive content and matter from other blogs will not be published.
For most generalized comments and for any other non-related article queries, please use Contact page to reach me. I will get back to you as soon as possible.
*Provide a valid email so that I can reach (if required) you personally at any time.
great help in understanding ViewStateMode