主题：for each 未将对象引用设置到对象的实例，已解决！

  For Each nd As WinForm.TreeNode In trv.AllNodes
                    Select Case nd.Level
                        Case 0 '看下是第几层节点,这边是第一层
                            If nd.Name <> "全部编码" Then '不等于,拿来的大于和小于呢,又不是数值
                                If nd.DataRow("上级组") = True Then
                                    txt = nd.DataRow("编码") & " " & nd.DataRow("编码名称")
                                    nd.Text = txt
                                    Output.Show(22)

                                End If

                            End If
                    End Select
                Next