Problem Using ViewState

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i have a function setlocation(); which bind my dropdownlist on pageload.
and if user select another location then on selectedindex i use following code:

C#

protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
        {
            string check = "";
                        check = ddlState.SelectedItem.Text;
            ViewState["statename"] = check;
        }

ON page load i use:

C#

if(ViewState["statename"]!=null)
               {
                   ddlState.SelectedItem.Text = ViewState["statename"].ToString();
               }
                else
                   {
                Setlocation();
                   }

in aspx:

XML

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
                       <ContentTemplate><asp:DropDownList ID="ddlState" AutoPostBack="true"   runat="server" style="height:28px; width:176px"
                               onselectedindexchanged="ddlState_SelectedIndexChanged">
                       </asp:DropDownList>
                     </ContentTemplate>
                           <Triggers>
                               <asp:AsyncPostBackTrigger ControlID="imgBtnCancel" EventName="Click" />
                           </Triggers>
                     </asp:UpdatePanel>

The problem is that onpage load the complier fall alwayz on else condition.why where i am wrong

Posted 12-Dec-10 21:14pm

balongi

Updated 12-Dec-10 21:55pm

Toniyo Jackson

v4

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Abdul Quader Mamun 13-Dec-10 3:16am

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Sandeep Mewara · Accepted Answer · 2010-12-12T21:28:00

Well, 2 things:
1. Sounds like you forgot to use the page 'IsPostback' property. Make sure that you are not rebinding the dropdown on every postback - if so, it will reset the selection.

2. Once IsPostback is in place, the else part would hit from 3rd time onwards. First time, fresh pageload, nothing in viewstate. 2nd time, again nothing as selectedindex change event is not yet hit. Once hit, it will set the viewstate now.After this, if you have any postback it will go to that part.

Now, not sure what you are trying to do but it does not look like the intended bevaiour or the way to do it.