what's wrong with this parameter?

[André]

Hi,

I made a detailsview for inserting data in the table.
I also made a dropdownlist which the selected value must be used for one of
the field in the detailsview.
In the <InsertParamete rs> tag, i removed the parameter 'lo' because i added
it from code-behind.
I put the 'DataKeyNames' as the primary key of the table in detailsview.

My problem is:
"No value given for one or more required parameters"

In aspx, i did:
<asp:SqlDataSou rce ID="SqlDataSour ce1" runat="server"
ConflictDetecti on="CompareAllV alues"
ConnectionStrin g="Provider=Mic rosoft.Jet.OLED B.4.0;Data
Source=c:\mytab le.mdb"
....
InsertCommand=" INSERT INTO [pc] ([na], [deft], [lo]) VALUES (?, ?, @lo)"
OldValuesParame terFormatString ="original_{ 0}"
ProviderName="S ystem.Data.OleD b"
<InsertParamete rs>
<asp:Paramete r Name="na" Type="String" />
<asp:Paramete r Name="deft" Type="Boolean" />
</InsertParameter s>

If i add this, it works (but still with this value)
<asp:Paramete r Name="anything" DefaultValue="1-45" Type="String" />

code-behind:
Protected Sub DropDownList1_S electedIndexCha nged(ByVal sender As Object,
ByVal e As System.EventArg s) Handles DropDownList1.S electedIndexCha nged
Dim lo As String
lo = DropDownList1.S electedValue
SqlDataSource1. InsertParameter s.Add("lo", lo)
End Sub
What did i not see?
Thanks for help
André