dropdownlist losing value on postback

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I am using Custom paging in Gridview. I have created a Control in which there is a dropdown to selece page size. Everything works fine but when i am refreshing page the dropdown lost it's value
here is my code

ASP.NET

<asp:DropDownList ID="ddlPageRowSize" EnableViewState="True" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlPageRowSize_SelectedIndexChanged">
                <asp:ListItem Value="10">10</asp:ListItem>
                <asp:ListItem Value="20">20</asp:ListItem>
                <asp:ListItem Value="50">50</asp:ListItem>
                <asp:ListItem Value="100">100</asp:ListItem>
            </asp:DropDownList>

on page load i am saving dropdown selected value in viewstate here is my code

C#

protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack) return;
        ViewState["PageSize"] = ddlPageRowSize.SelectedItem.Value;
    }
// suppose i have selected 100 from dropdown and then refresh the page 
// ddlPageRowSize.SelectedItem.Value always returns 10

what wrong i am doing can anyone suggest....

Posted 7-Jan-14 20:28pm

Vishal Pand3y

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Naz_Firdouse · Answer 1 · 2014-01-08T02:50:00

your page load event should be soemthing like this

C#

protected void Page_Load(object sender, EventArgs e)
    {

  //  if (!Page.IsPostBack)
  //  {
     //do something
   // }
   // else
   // {
     //   ddlPageRowSize.SelectedIndex= Convert.ToInt32(Session["index"]);

         if(Session["index"] == null)
         {
             //do something
         }
         else
         {
             ddlPageRowSize.SelectedIndex= Convert.ToInt32(Session["index"]);  
         }


    }

where you set the value to the session in the ddlPageRowSize_SelectedIndexChanged event like

C#

protected void ddlPageRowSize_SelectedIndexChanged(object sender, EventArgs e)
{
    Session["index"] = ddlPageRowSize.SelectedIndex;
}

Sibasisjena · Answer 2 · 2014-01-07T20:46:00

Solution 1

Selected="True" to your list item will solve your problem.

ASP.NET

<asp:DropDownList ID="ddlPageRowSize" EnableViewState="True" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlPageRowSize_SelectedIndexChanged">
                <asp:ListItem Selected="True" Value="10">10</asp:ListItem>
                <asp:ListItem Value="20">20</asp:ListItem>
                <asp:ListItem Value="50">50</asp:ListItem>
                <asp:ListItem Value="100">100</asp:ListItem>
            </asp:DropDownList>

please use the following code.

C#

protected void Page_Load(object sender, EventArgs e)
{

    if (Session["PageSize"] != null)
        ddlPageRowSize.SelectedValue = Convert.ToString(Session["PageSize"]);

}

protected void ddlPageRowSize_SelectedIndexChanged(object sender, EventArgs e)
{
    Session["PageSize"] = ddlPageRowSize.SelectedValue;
}

Posted 7-Jan-14 20:46pm

Sibasisjena

Updated 7-Jan-14 23:47pm

v5

Comments

Vishal Pand3y 8-Jan-14 2:56am

but when i will refresh the page, it will return always 100 whether i have selected 50 from dropdown

Sibasisjena 8-Jan-14 3:17am

Check my solution 2

Sibasisjena 8-Jan-14 3:14am

Ok do one thing in the ddlPageRowSize_SelectedIndexChanged event save the selected value in view state. Assign the saved value in the page load again.

Vishal Pand3y 8-Jan-14 3:53am

No its not working after refreshing page i am getting 10 always

Sibasisjena 8-Jan-14 5:02am

I have changed my solution please check it.

Vishal Pand3y 8-Jan-14 5:09am

no you aren't getting my point. Suppose i have selected 100 from dropdown and then refresh the page (by browser refresh button), i am getting 10 in dropdown. dropdown is not maintaining it's state although i have written EnableViewState="True" in dropdown