get data from database in aspx

Question

i am using VS 2010 to develop a site that gets some data from a database.

but i just keep getting this error.

'No value given for one or more required parameters.'

here is my code

Public Function getSessionDetails(ByVal roomId As String) As ArrayList

Dim sql As String
    sql = "SELECT * FROM Table1 WHERE RoomId = ?"
    Dim dbComm As New OleDbCommand(sql, dbConn)

    'dbComm.Connection.Open()
    dbComm.CommandText = sql
    dbComm.Parameters.Add("RoomId", System.Data.OleDb.OleDbType.BSTR).Value = roomId
    dbConn.Open()
    'dbComm.ExecuteNonQuery()


    Dim dbRead As OleDbDataReader = dbComm.ExecuteReader() 'System.Data.CommandBehavior.CloseConnection)

    Dim arr As New ArrayList

    Try
        While dbRead.Read()
            arr.Add(New SessionDetails(dbRead.GetValue(2).ToString, dbRead.GetValue(3).ToString, dbRead.GetValue(4).ToString, dbRead.GetValue(6).ToString, _
                                       dbRead.GetValue(5).ToString, dbRead.GetValue(7).ToString, dbRead.GetValue(8).ToString))
        End While
    Catch ex As Exception

    End Try

    Try
        'sort arr by date using bubble
        For i As Integer = 1 To arr.Count - 1
            Dim sesTop As SessionDetails = arr(i)
            Dim sesBot As SessionDetails = arr(i - 1)
            Dim sesTmp As SessionDetails

            If sesBot.sessionDate < sesTop.sessionDate Then
                'swap them
                sesTmp = arr(i)
                arr(i) = arr(i - 1)
                arr(i - 1) = sesTmp
                i = 0
            ElseIf sesBot.sessionDate = sesTop.sessionDate And sesBot.StartTime < sesTop.StartTime Then
                'swap them
                sesTmp = arr(i)
                arr(i) = arr(i - 1)
                arr(i - 1) = sesTmp
                i = 0
            End If
        Next
    Catch ex As Exception

    End Try

    'Dim se As SessionDetails
    'For Each se In arr
    '    If se.sessionDate < Now Then
    '        arr.Remove(se)
    '    End If
    'Next

    dbRead.Close()
    dbConn.Close()

    Return arr
End Function

Thanks for any help

Answer 1

Change these two lines

sql = "SELECT * FROM Table1 WHERE RoomId = @RoomId"


dbComm.Parameters.Add("@RoomId", System.Data.OleDb.OleDbType.BSTR).Value = roomId

Answer 2

sql = "SELECT * FROM Table1 WHERE RoomId = ?--this is wrong query.

right query is 'sql = "SELECT * FROM Table1 WHERE RoomId = @RoomId'

dbComm.Parameters.Add("@RoomId", System.Data.OleDb.OleDbType.BSTR).Value = RoomId