Populate DropDown by Clicking Button

Hi

I am trying to select an item in a drop down by clicking a command button but I keep on getting an error saying "Cannot have multiple items in drop down"

The drop down does not have any duplicated so I am not sure why this is happening

Code is below.... Any ideas??

thanks


      Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)            
            If Not Page.IsPostBack Then
            ddlCountry.DataSource = DataAccess.ReaderFromSP("SELECT * FROM tblCountry ORDER BY Country_Name ASC")
            ddlCountry.DataTextField = "Country_Name"
            ddlCountry.DataValueField = "Country_ID"
            
            ddlCountry.DataBind()
            End If
      End Sub

'-- button click event
      Protected Sub cmdUseThis_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim objCountryID As Object = DataAccess.getScalarResult("SELECT City_Country_ID FROM tblCity WHERE City_ID = " & listLocInfo.SelectedValue)

            ddlCountry.Items.FindByValue(objCountryID).Selected = True
            
      End Sub
patelajkAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

justin-clarkeCommented:
You may need to use ddlCountry.Items.Clear() before each DataRead.
0
patelajkAuthor Commented:
tried putting this at the top like below but i get a "Object reference not set to an instance of an object" error as the drop down is cleared:
     Protected Sub cmdUseThis_Click(ByVal sender As Object, ByVal e As System.EventArgs)
ddlCountry.Items.Clear()
Dim objCountryID As Object = DataAccess.getScalarResult("SELECT City_Country_ID FROM tblCity WHERE City_ID = " & listLocInfo.SelectedValue)

            ddlCountry.Items.FindByValue(objCountryID).Selected = True
           
      End Sub

0
Blackninja2007Commented:
You need to to check if the object exists before clearing it.

if not(ddlcountry is nothing) then
  ddlcountry.items.clear()
end if
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
ASP.NET

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.