主题：事件代码冲突

老师，麻烦看一下下面代码是有冲突吗？科目类别根据科目名称从会计科目表同步过来，余额计算公式根据科目类别的值决定。理论上不存在冲突啊，现在就是输入科目类别为2负债和4权益的科目就会报错。

If e.DataCol.Name = "科目名称" Then '发生变化的是产品编号吗?
    '在产品表找出该产品
    Dim dr As DataRow
    dr = DataTables("会计科目表").Find("科目名称 = '" & e.DataRow("科目名称") & "'" )
    If dr IsNot Nothing '如果找到, 则设置各列内容
        e.DataRow("科目代码")= dr("科目代码")
        e.DataRow("科目类别")= dr("科目类别")
    End If
End If
Select Case e.DataCol.Name
    Case "科目名称","借方","贷方","科目类别"
        Dim dr As DataRow
        Dim mr As DataRow = e.DataRow
        Dim drs As List(of DataRow)
        dr = e.DataTable.Find("[_SortKey] < " & mr("_SortKey") & " And [科目名称] = '" & mr("科目名称") & "'", "[_SortKey] Desc")
       
        If dr Is Nothing Then
            If mr("科目类别") = "2负债" OrElse mr("科目类别") = "4权益" Then
                If e.DataRow.IsNull("科目类别") Then '身份证号码是否为空
                    Return '如果为空,则清除出生日期
                Else
                   
                    mr("余额") = mr("贷方") - mr("借方")
                    mr("方向") = "贷"
                End If
            Else
                mr("余额") = mr("借方") - mr("贷方")
                mr("方向") = "借"
                dr = mr
            End If
           
           
        End If
        drs = e.DataTable.Select("[_SortKey] >= " & dr("_SortKey") & " And [科目名称] = '" & dr("科目名称") & "'", "[_SortKey]")
        For i As Integer = 1 To drs.Count - 1
           
            If dr("科目类别") = "2负债" OrElse dr("科目类别") = "4权益" Then
                If e.DataRow.IsNull("科目类别") Then '身份证号码是否为空
                    Return '如果为空,则清除出生日期
                Else
                    drs(i)("余额") = drs(i-1)("余额") + drs(i)("贷方") - drs(i)("借方")
                    drs(i)("方向") = "贷"
                End If
            Else
                drs(i)("余额") = drs(i-1)("余额") + drs(i)("借方") - drs(i)("贷方")
                drs(i)("方向") = "借"
               
            End If
        Next
        If e.DataCol.Name = "科目名称" AndAlso e.OldValue IsNot Nothing AndAlso e.OldValue <> e.NewValue Then
            dr = e.DataTable.Find("[_SortKey] < " & mr("_SortKey") & " And [科目名称] = '" & e.OldValue & "'", "[_SortKey] Desc")
            If dr Is Nothing Then
                dr = e.DataTable.Find("[科目名称] = '" & e.OldValue & "'", "[_SortKey]")
                If dr IsNot Nothing Then
                   
                    If dr("科目类别") = "2负债" OrElse dr("科目类别") = "4权益" Then
                        If e.DataRow.IsNull("科目类别") Then '身份证号码是否为空
                            Return '如果为空,则清除出生日期
                        Else
                           
                            dr("余额") = dr("贷方") - dr("借方")
                            dr("方向") = "贷"
                        End If
                    Else
                        dr("余额") = dr("借方") - dr("贷方")
                        dr("方向") = "借"
                       
                    End If
                End If
            End If
            If dr IsNot Nothing Then
                drs = e.DataTable.Select("[_SortKey] >= " & dr("_SortKey") & " And [科目名称] = '" & dr("科目名称") & "'", "[_SortKey]")
                For i As Integer = 1 To drs.Count - 1
                   
                    If dr("科目类别") = "2负债" OrElse dr("科目类别") = "4权益" Then
                        If e.DataRow.IsNull("科目类别") Then '身份证号码是否为空
                            Return '如果为空,则清除出生日期
                        Else
                           
                            drs(i)("余额") = drs(i-1)("余额") + drs(i)("贷方") - drs(i)("借方")
                            drs(i)("方向") = "贷"
                        End If
                    Else
                       
                        drs(i)("余额") = drs(i-1)("余额") + drs(i)("借方") - drs(i)("贷方")
                        drs(i)("方向") = "借"
                    End If
                   
                Next
            End If
        End If
End Select