Question

i use asp.net and this code in aspx page:

public partial class Default : System.Web.UI.Page
{
    string _Name;

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            _Name = "Maikel";
            ViewState["Name"] = _Name;
        }
    }

    protected void btnAddName_Click(object sender, EventArgs e)
    {
        if (ViewState["Name"] == null)
        {
            txtName.Text = "Empty";
        }
        else
        {
            txtName.Text = ViewState["Name"].ToString();
        }
    }
}

its OK. and display “Maikel” in textbox.
But when I use this code:

<%@ Page Language="C#" AutoEventWireup="true" **ViewStateMode="Disabled" EnableViewState="true**" CodeBehind="Default.aspx.cs" Inherits="WebApplication3.Default" %>

ViewState["Name"] is Empty! and display “Empty” in textbox. why?

plese help me for use ViewState with ViewStateMode="Disabled" EnableViewState="true".

Edit:

I use master page and (web from use master page), and write this code in master page:

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site1.master.cs" ViewStateMode="Disabled" EnableViewState="true" Inherits="WebApplication3.Site1" %>

and code ViewState["Name"] in code behind page(web from use master page), ViewState is not Empty!! why?

Answer 1

In your case you have disabled the ViewState property for the whole page by setting ViewStateMode="Disabled" at page level. That is why you are not getting anything in the view state.

ASP.NET View State Overview

To disable view state by default for an entire page, set the
ViewStateMode attribute of the @ Page directive to Disabled.

Control.ViewStateMode Property (MSDN)

To disable view state for a page and to enable it for a specific
control on the page, set the EnableViewState property of the page
and the control to true, set the ViewStateMode property of the page to
Disabled, and set the ViewStateMode property of the control to
Enabled.

The ViewStateMode property of a page or a control has an effect only
if the EnableViewState property is set to true. If the EnableViewState
property is set to false, view state will be turned off even if the
ViewStateMode property is set to Enabled.

EDIT:
To Use ViewState in Page.

You can place all your controls inside a panel, and for that panel you can set the ViewState to false. At Page level enable ViewStateMode and you will be able to use the ViewState in the code behind

For MasterPage you can disable the ViewState on ContentPlaceHolder

<asp:ContentPlaceHolder ID="HeadContent" runat="server" EnableViewState="false">
</asp:ContentPlaceHolder>

and at Master page level enable the ViewStateMode