Hello everybody! I have an idea how to use listbox items for query, but it doesn't work. "Input string was not in a correct format."

What is wrong with this, is this good idea or not? Thank you for help!



Public Sub popisUpita_SelectedIndexChanged(sender As Object, e As EventArgs)
For Each izabraniUpit As System.Web.UI.WebControls.ListItem In popisUpita.Items
If izabraniUpit.Selected Then
izabraniUpiti.AppendFormat("{0},", izabraniUpit.Value)

End If
Next
izabraniUpiti.Remove(izabraniUpiti.Length - 1, 1)
'Remove last comma
End Sub

Using objConn As New OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0; " & "DATA SOURCE=" & Server.MapPath("HR.mdb;"))
Using objCmd As New OleDbCommand("Select [Skraćena tvrtka-naziv],", objConn)

objConn.Open()
objCmd.CommandText += " izabraniUpiti.ToString()"
' objCmd.CommandText.Remove(objCmd.CommandText.Lengt h - 1, 1)
objCmd.CommandText += " WHERE (Općina = '" & izabranaOpcina & "')"
objCmd.CommandType = CommandType.Text

Dim DR As OleDbDataReader = objCmd.ExecuteReader()
upit.DataSource = DR
upit.DataBind()