代码问题~ datareader

其实我之前也问过问题，但没人理我，最后是自己搞定的，
大家不要那么冷漠，帮帮我们这些新人吧
我想自动生成id，但vb说
dbOrderReader = oledbcommand.ExecuteReader()
错 误：Command text was not set for the command object.
这是我的代码
Public Sub DBID()
        Dim oledbcommand As OleDbCommand
        Dim oledbconnection As OleDbConnection
        Dim dbOrderReader As OleDbDataReader
        Dim strSQL As String
        oledbconnection = New OleDbConnection(strConnection)
        oledbcommand = New OleDbCommand
        oledbcommand.Connection = oledbconnection
        oledbcommand.Connection.Open()
        Dim temp As Integer
        strSQL = "SELECT MAX(OrderID) FROM tblOrder "
        dbOrderReader = oledbcommand.ExecuteReader()
        oledbcommand.CommandType = CommandType.Text
        If dbOrderReader.HasRows Then
            While dbOrderReader.Read()
                temp = dbOrderReader.Item("OrderID") + 1
            End While
        End If
        dbOrderReader.Close()
        oledbcommand.CommandText = strSQL
        oledbcommand.ExecuteNonQuery()
        oledbcommand.Connection.Close()
        txtID.Text = temp ' result will appear in textbox txtId
    End Sub
End Class
谢谢了各位