DropDown SelectedIndex Changed Event firing

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I have a dropdown which has a selectedIndexchanged event which fires on first postback(a button click) and it stops firing for the next postbacks.

XML

<asp:DropDownList ID="AreaDD" Width="150px" AutoPostBack="True" runat="server" OnSelectedIndexChanged="AreaDD_SelectedIndexChanged">
                                </asp:DropDownList>

Why it is firing for button click event?

Thanks in Advance

Posted 27-May-14 0:58am

idhris2011

Updated 27-May-14 0:59am

v2

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Bh@gyesh 27-May-14 7:00am

SelectedIndexChanged event fires only when you change item in dropdownlist. It will not fire on initial formload postback.

Have you explicitly call this event in page_load event?

idhris2011 27-May-14 7:18am

No, the event was not explicitly called anywhere. When I click the button, the selectedIndex event was called and the it comes to the button click event and when I click the button again, it directly comes to the button click event and selectedIndex was not called.

Bh@gyesh 27-May-14 7:24am

Ideally, when u click on button the selectedindexchanged event must not be called. IT should called only when you change selected items from dropdown.
Can you share your code here?

Bh@gyesh 27-May-14 7:31am

Add property - EnableViewState = True in dropdownlist.

idhris2011 27-May-14 7:38am

It works same even setting EnableViewState = True, if False then I am losing the values in dropdown

idhris2011 27-May-14 7:32am

protected void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
{
//binds the drop down
}
}

protected void AreaDD_SelectedIndexChanged(object sender, System.EventArgs e)
{
Response.write("Area");
}
protected void UpdateButton_Click(object sender, System.EventArgs e)
{
Response.write("Updated");
}

When I click the update button, I am getting
Area
Updated

Bh@gyesh 27-May-14 7:35am

Have you tried "EnableViewState = True" in dropdownlist?

idhris2011 27-May-14 7:39am

t works same even setting EnableViewState = True, if False then I am losing the values in dropdown

Bh@gyesh 27-May-14 8:06am

Do you have any render or prerender event? I have tried at my side and it is working fine.

idhris2011 28-May-14 1:42am

In my page load, am binding the dropdownlist and after that I am using querystring to select the values from the dropdown.

ListItem lixx = DD.Items.FindByValue("Area");
if (lixx != null)
DD.Items.FindByValue("Area").Selected = true;

Bh@gyesh 30-May-14 0:27am

Ahh, is this code in "if(!Page.IsPostback)" condition?

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Raul Iloc · Answer 1 · 2014-05-27T01:08:00

1. Your ASP.NET code will generate postback each time you select a new item in the list, and it will not generate any postback if you do not select other item (or your item list has only one item and this item was already selected).

2. If you want that the event to be fired only when you click on submit button from your page, and the current index was changed before to press on button, you have to change the property AutoPostBack to false.

Phanindra Baddula · Answer 2 · 2014-05-27T03:09:00

on selectedindexchangedevent... at End Of Event set the property AreaDD.AutoPostBack=false; in .cs file.

C#

protected void timezone_SelectedIndexChanged(object sender, EventArgs e)
      {


/// Add your Code for first index change /////////////



          timezone.AutoPostBack = false;

      }

DropDown SelectedIndex Changed Event firing

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