DropDownList in VB.net

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I have a dropdownlist ctrl in my page.

I code to set datasoure for dropdownlist in codebehide file.

My question is whenever the page is postback the dropdownlist datasource is nothing and the following code run?

I would like to run the code once page first load.

VB

If UnitName_ddl.DataSource Is Nothing Then
                Dim dt As New DataTable("Unit_tbl")
                dt.Columns.Add("UnitName")
                dt.Rows.Add("--Select UnitName--")
                dt.Rows.Add("KOTAK")
                dt.Rows.Add("ICICI BANK LTD")
                UnitName_ddl.DataSource = dt
                UnitName_ddl.DataBind()
            End If

Posted 6-Sep-10 21:01pm

sankar guru

Updated 6-Sep-10 21:28pm

Dalek Dave

v2

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Dalek Dave 7-Sep-10 3:28am

Minor Edit for Grammar.

2 solutions

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Sunasara Imdadhusen · Answer 1 · 2010-09-06T21:27:00

Solution 1

Hi Usankardurai,

I think you will have to reset datasoure at every postback event.

Please write the code out side of the PostBack

//Write code here..
if(!IsPostback)
{
//Remove code from here..
}

Please do let me know, if you still have problem. :)

Thanks,
Imdadhusen

Posted 6-Sep-10 21:27pm

Sunasara Imdadhusen

Comments

sankar guru 7-Sep-10 3:32am

i just write the code inside
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
//my code

End Sub
and i set DataTextField and DataValueField as "UnitName"

How to prevent Data Lost each time ?

Sunasara Imdadhusen 7-Sep-10 7:20am

I think i am not cleared about problem.
what you would to like. You have to maintain or prevent data during postback?

LNogueira · Answer 2 · 2010-09-07T02:52:00

If you have viewstate active for your control try on page_load event:

If not ispostback Then

             Dim dt As New DataTable("Unit_tbl")
              dt.Columns.Add("UnitName")
              dt.Rows.Add("--Select UnitName--")
              dt.Rows.Add("KOTAK")
              dt.Rows.Add("ICICI BANK LTD")
              UnitName_ddl.DataSource = dt
              UnitName_ddl.DataBind


End If

If viewstate is disabled you have to load your values each time the page is postedback.