1、如何让考核序号自动增加到第18时，出现提示，注意，你的考核序号已经增加到18条

Select e.DataCol.Name
    Case "文档号"
        If e.DataRow.IsNull("文档号") Then
            e.DataRow("考核序号") = Nothing
        Else
            Dim lb As String = e.DataRow("文档号")
            If e.DataRow("考核序号").StartsWith(lb) = False
                Dim max As String
                Dim idx As Integer
                max = e.DataTable.Compute("Max(考核序号)","文档号 = \'" & lb & "\'")
                If max > "" Then \'
                    idx = CInt(max.Substring(5,3)) + 1
                Else
                    idx = 1
                End If
                e.DataRow("考核序号") = lb & Format(idx,"000")
            End If
        End If
End Select

2、如何根据考核序号判断，不再填入已经存在的内容。

Dim f As New Filler
f.SourceTable = DataTables("出勤表")
f.SourceCols = "时间,考核事实,依据,加扣分值,考核序号"

f.DataTable = DataTables("文档号")

f.DataCols = "时间,考核事实,依据,加扣分值,考核序号"

f.Fill() \'

求大神帮忙啦

2、如何根据考核序号判断，不再填入已经存在的内容。

Dim f As New Filler
f.SourceTable = DataTables("出勤表")
f.SourceCols = "时间,考核事实,依据,加扣分值,考核序号"

f.DataTable = DataTables("文档号")

f.DataCols = "时间,考核事实,依据,加扣分值,考核序号"

f.Filter = "编号 = 55526"

f.Fill() \'

开少了个编号条件，现在是，执行一次，就填一次，再执行，就把先前已经重复的内容又填充进去，能不能加个语句在填充时，自动根据考核序号判断已经存在的内容不在填充，求大神帮忙啦

Dim nma() As String = {"A1","A2","A3","A4"} \'A表数据来源列
Dim nmb() As String = {"B1","B2","B3","B4"}\'B表数据接收列
For Each dr As DataRow In DataTables("表A").DataRows
    Dim dr2 As DataRow = DataTables("表B").Find("A2=\'" & dr("B2") & "\'")
    If dr2 Is Nothing Then
        For i As Integer = 0 To nma.Length - 1
            dr2(nmb(i)) = dr(nma(i))
        Next
    End If
Next

测试时，提示错误：System.Reflection.TargetInvocationException: 调用的目标发生了异常。 ---> System.NullReferenceException: 未将对象引用设置到对象的实例。

Dim nma() As String = {"A1","A2","A3","A4"} \'A表数据来源列
Dim nmb() As String = {"B1","B2","B3","B4"}\'B表数据接收列
For Each dr As DataRow In DataTables("表A").DataRows
    Dim dr2 As DataRow = DataTables("表B").Find("A2=\'" & dr("B2") & "\'")
    If dr2 Is Nothing Then
        dr2 = DataTables("表B").AddNew()
        For i As Integer = 0 To nma.Length - 1
            dr2(nmb(i)) = dr(nma(i))
        Next
    End If
Next

测试结果：由于Nothing Then对数值列空值的判断会返回零，所以每次执行就会把表A的空值行不断导入表B，并在数值列显示0，如何解决，不让空值行导入表B？知道原因，不知道方法！