ViewState issue with asp.net

Question

I have below code,

    If Not Page.IsPostBack Then
        ViewState("ItemID") = 0
        If Not Request.QueryString("id") Is Nothing Then
            ViewState("ItemID") = Request.QueryString("id")
            ItemID = Integer.Parse(ViewState("ItemID"))
        End If
        If ItemID > 0 Then
            ltrTitle.Text = "Edit Item"
            bindEditData()
        End If
    End If

When I tried to get ViewState("ItemID") on button click, it returns nothing. Any help?

Are you intentionally using ViewState instead of Session? [What is the difference between SessionState and ViewState?](http://stackoverflow.com/a/733486/1115360) — Andrew Morton, Apr 08 '16 at 21:13
Could you give us more information, for example: where this code is used, the body of bindEditData and the body of button click. — Henrique, Apr 11 '16 at 12:46

score 1 · Accepted Answer · answered Apr 11 '16 at 12:20

I see that you have your code in not postback method. So once your page postback, viewstate value will be lost.

Please change your code to,

ViewState("ItemID") = 0
If Not Request.QueryString("id") Is Nothing Then
    ViewState("ItemID") = Request.QueryString("id")
    ItemID = Integer.Parse(ViewState("ItemID"))
End If
If Not Page.IsPostBack Then        
    If ItemID > 0 Then
        ltrTitle.Text = "Edit Item"
        bindEditData()
    End If
End If

ConnorsFan · Answer 2 · 2016-04-08T21:07:57.137

The ViewState is probably turned off on your page. The EnableViewState attribute is set to false or the ViewStateMode attribute is set to Disabled:

<%@ Page EnableViewState="false" ... />
<%@ Page ViewStateMode="Disabled" ... />

You can enable the ViewState by changing these settings:

<%@ Page EnableViewState="true" ... />
<%@ Page ViewStateMode="Enabled" ... />

These are the default settings, and are necessary only if the ViewState is disabled at the application level (in Web.config).

ViewState issue with asp.net

2 Answers2