Dynamically build dropdownlist box

[DaveF]

When I select the first dropdownlist box, I need to be able to make several
dropdownlist boxes on the fly and populate them from the database. Is this
possible? If so, HOW?

--

David Fetrow
Helixpoint LLC.
da***@helixpoint.com

[Ken Cox [Microsoft MVP]]

Hi Dave,

The easiest way is to add a PlaceHolder control to your page. Then, create
the dropdownlist on the fly, add the items to the ddl from the database and
finally add the ddl to the PlaceHolder. Here's the idea:

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
End Sub

Private Sub DropDownList1_SelectedIndexChanged _
(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles DropDownList1.SelectedIndexChanged
Dim ddlData As New DropDownList
Dim dt As DataTable
Dim lstItem As ListItem
Dim dr As DataRow
dt = CreateDataSource()
For Each dr In dt.Rows
lstItem = New ListItem
lstItem.Text = dr.Item("StringValue")
lstItem.Value = dr.Item("IntegerValue")
ddlData.Items.Add(lstItem)
Next
PlaceHolder1.Controls.Add(ddlData)
End Sub

Function CreateDataSource() As DataTable
Dim dt As New DataTable
Dim dr As DataRow
dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))
dt.Columns.Add(New DataColumn("Boolean", GetType(Boolean)))
Dim i As Integer
For i = 0 To 8
dr = dt.NewRow()
dr(0) = i
dr(1) = "Item " + i.ToString()
dr(2) = 1.23 * (i + 1)
dr(3) = (i = 4)
dt.Rows.Add(dr)
Next i
Return dt
End Function 'CreateDataSource

<form id="Form1" method="post" runat="server">
<P>
<asp:DropDownList id="DropDownList1" runat="server" AutoPostBack="True">
<asp:ListItem Value="--Select--">--Select--</asp:ListItem>
<asp:ListItem Value="Items">Items</asp:ListItem>
<asp:ListItem Value="Colours">Colours</asp:ListItem>
</asp:DropDownList></P>
<P>
<asp:PlaceHolder id="PlaceHolder1" runat="server"></asp:PlaceHolder></P>
</form>

Does this help?

Ken
Microsoft MVP [ASP.NET]
Toronto
"DaveF" <df*****@geodecisions.com> wrote in message
news:Ob**************@tk2msftngp13.phx.gbl...

When I select the first dropdownlist box, I need to be able to make
several
dropdownlist boxes on the fly and populate them from the database. Is this
possible? If so, HOW?

--

David Fetrow
Helixpoint LLC.
da***@helixpoint.com