What is wrong with this code to populate a DropDownList?

What is wrong with this code to populate a DropDownList?

Can somebody Help me?

Tnx

RMac
================================================== ===================================
WebForm.aspx.vb

Imports System
Imports System.Data
Imports System.Data.OleDb
Imports System.Threading.Thread
Imports System.Web.UI.WebControls.DropDownList
Public Class WebForm2
Inherits System.Web.UI.Page
Protected WithEvents DropDownList1 As
System.Web.UI.WebControls.DropDownList

#Region " Web Form Designer Generated Code "

'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()

End Sub

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub

#End Region
Public dbRead
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here
Dim sql
Dim myConnection As New
OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; data source=" &
Server.MapPath("/db/ProdutosFotografia.mdb"))

sql = "SELECT Distinct Marca FROM Produtos"
Dim myCommand As New OleDbCommand(sql, myConnection)
myCommand.Connection.Open()
Dim myReader As OleDbDataReader =
myCommand.ExecuteReader(CommandBehavior.CloseConne ction)
While myReader.Read()
'Console.WriteLine(myReader.GetString(0))
DropDownList1.Items.Add(myReader.GetString(0))
End While
myReader.Close()
myConnection.Close()
End Sub
End Class

re: What is wrong with this code to populate a DropDownList?

Are you getting an error?

You could just use

dropdownlist1.DataSource = dr
dropdownlist1.DataTextField = "Marca"
dropdownList1.DataBind()

but it'll do the same..null reference? not displaying what you thought it
hsould?

Karl

--
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http://www.openmymind.net/ - New and Improved (yes, the popup is annoying)
http://www.openmymind.net/faq.aspx - unofficial newsgroup FAQ (more to
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"Rui Macdonald" <ruimacdonald@hotmail.com> wrote in message
news:%23iZUUL3QFHA.2604@TK2MSFTNGP10.phx.gbl...[color=blue]
> What is wrong with this code to populate a DropDownList?
>
> Can somebody Help me?
>
> Tnx
>
> RMac
>[/color]
================================================== ==========================
=========[color=blue]
> WebForm.aspx.vb
>
> Imports System
> Imports System.Data
> Imports System.Data.OleDb
> Imports System.Threading.Thread
> Imports System.Web.UI.WebControls.DropDownList
> Public Class WebForm2
> Inherits System.Web.UI.Page
> Protected WithEvents DropDownList1 As
> System.Web.UI.WebControls.DropDownList
>
> #Region " Web Form Designer Generated Code "
>
> 'This call is required by the Web Form Designer.
> <System.Diagnostics.DebuggerStepThrough()> Private Sub
> InitializeComponent()
>
> End Sub
>
> Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Init
> 'CODEGEN: This method call is required by the Web Form Designer
> 'Do not modify it using the code editor.
> InitializeComponent()
> End Sub
>
> #End Region
> Public dbRead
> Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> 'Put user code to initialize the page here
> Dim sql
> Dim myConnection As New
> OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; data source=" &
> Server.MapPath("/db/ProdutosFotografia.mdb"))
>
> sql = "SELECT Distinct Marca FROM Produtos"
> Dim myCommand As New OleDbCommand(sql, myConnection)
> myCommand.Connection.Open()
> Dim myReader As OleDbDataReader =
> myCommand.ExecuteReader(CommandBehavior.CloseConne ction)
> While myReader.Read()
> 'Console.WriteLine(myReader.GetString(0))
> DropDownList1.Items.Add(myReader.GetString(0))
> End While
> myReader.Close()
> myConnection.Close()
> End Sub
> End Class
>
>[/color]

re: What is wrong with this code to populate a DropDownList?

Is the problem that you're getting is that on postbacks you're not getting
the rigth item selected? If so, then only build the DDL if it's not a postback.
You shouldn't repopulate the list when there is a postback as that removes
all the entires (and the one the user selected). So wrap all your code in
Page_Load in something like this:

Sub Page_Load()
If Not IsPostBack Then
' all of your code here
End If
End Sub

-Brock
DevelopMentor
http://staff.develop.com/ballen


[color=blue]
> What is wrong with this code to populate a DropDownList?
>
> Can somebody Help me?
>
> Tnx
>
> RMac
> ================================================== ====================
> =============== WebForm.aspx.vb
>
> Imports System
> Imports System.Data
> Imports System.Data.OleDb
> Imports System.Threading.Thread
> Imports System.Web.UI.WebControls.DropDownList
> Public Class WebForm2
> Inherits System.Web.UI.Page
> Protected WithEvents DropDownList1 As
> System.Web.UI.WebControls.DropDownList
> #Region " Web Form Designer Generated Code "
>
> 'This call is required by the Web Form Designer.
> <System.Diagnostics.DebuggerStepThrough()> Private Sub
> InitializeComponent()
> End Sub
>
> Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Init
> 'CODEGEN: This method call is required by the Web Form
> Designer
> 'Do not modify it using the code editor.
> InitializeComponent()
> End Sub
> #End Region
> Public dbRead
> Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> 'Put user code to initialize the page here
> Dim sql
> Dim myConnection As New
> OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; data source=" &
> Server.MapPath("/db/ProdutosFotografia.mdb"))
>
> sql = "SELECT Distinct Marca FROM Produtos"
> Dim myCommand As New OleDbCommand(sql, myConnection)
> myCommand.Connection.Open()
> Dim myReader As OleDbDataReader =
> myCommand.ExecuteReader(CommandBehavior.CloseConne ction)
> While myReader.Read()
> 'Console.WriteLine(myReader.GetString(0))
> DropDownList1.Items.Add(myReader.GetString(0))
> End While
> myReader.Close()
> myConnection.Close()
> End Sub
> End Class[/color]