问,如下语句为什么出错?

Question

Dim ds As DataSet
    Dim ConnectionString As SqlConnection = New SqlConnection(System.Configuration.ConfigurationSettings.AppSettings("ConnectionString"))
    Dim rsda As SqlDataAdapter
    Dim MyCommand As SqlCommandConnectionString.Open()
            Dim sqltran As SqlTransaction = ConnectionString.BeginTransaction
            Try
                SQLLJA = "insert into 订单总表 (订单日期,建立者,接收者) VALUES (GETDATE(),'" + Session("userloginwang") + "','" + AKEY + "')"
                MyCommand = New SqlCommand(SQLLJA, ConnectionString)
                MyCommand.Transaction = sqltran
                MyCommand.ExecuteNonQuery()
                rsda = New SqlDataAdapter("select max(订单号) AS DDH FROM 订单总表 WHERE 建立者='" + Session("userloginwang") + "'", ConnectionString)
                ds = New DataSet
                rsda.Fill(ds, "abcd")
                la5.Text = Trim(ds.Tables("abcd").Rows(0).Item("ddh"))
                rsda = New SqlDataAdapter("SELECT DISTINCT SPMLID FROM 订单临时 where yhdlmc='" + Session("userloginwang") + "'", ConnectionString)
                ds = New DataSet
                rsda.Fill(ds, "ABCD")
                For a = 0 To ds.Tables("ABCD").Rows.Count - 1
                    If SQLLJ = "" Then
                        SQLLJ = Trim(ds.Tables("ABCD").Rows(a).Item("SPMLID"))
                    Else
                        SQLLJ = SQLLJ + "," + Trim(ds.Tables("ABCD").Rows(a).Item("SPMLID"))
                    End If
                Next     LINE = "insert into 正式订单 (AA,BB,CC) VALUES ('1','2','3')"
                MyCommand = New SqlCommand(LINE, ConnectionString)
                MyCommand.Transaction = sqltran
                MyCommand.ExecuteNonQuery()
                sqltran.Commit()
                ConnectionString.Close()
 Catch ex As Exception
                sqltran.Rollback()
                ConnectionString.Close()
                Response.Write("<script language=javascript>alert('对不起 由于服务器忙 提交失败 请再次重试');</script>")
            End Try当程序执行到ds = New DataSet
                rsda.Fill(ds, "abcd") 时提示
当分配给命令的连接处于挂起的本地事务中时，命令必须具有事务对象才能执行。该命令的 Transaction 属性尚未初始化。
该如何解决呢?