DataColChanged:

Dim dr As DataRow = e.DataRow
Select Case e.DataCol.Name
    Case "客户名称"
        If dr.IsNull("客户名称") Then
            Return
        Else
            dr("客户拼音") = getpy(dr("客户名称"),True)
        End If
    Case "联系人"
        If dr.IsNull("联系人") Then
            Return
        Else
            dr("客户拼音") =getpy(dr("客户名称"),True) & getpy(dr("联系人"),True)
        End If
    Case "所属_省市"
        dr("所属_市") = Nothing
        dr("所属_县市") = Nothing
    Case "所属_市"
        dr("所属_县市") = Nothing
    Case "所属_县市"
        Dim kfdm As String
        Dim xlh As Integer
        Dim kfdmdata As DataRow = DataTables("营销部").Find(" 市场片区_省市 = \'" & e.DataRow("所属_省市") & "\' and 市场片区_县市 = \'" & e.DataRow("所属_县市") &"\'")
        kfdm = kfdmdata("市场代码")
        kfdm = kfdm.trim()
        Dim last As new SQLCommand
        Dim last2 As new SQLCommand
        With last
            .ConnectionName =  "销售系统"
            .CommandText = "select [顺序号] from {编号} where [前缀] = \'"& kfdm &"\' and [表名] = \'客户档案\'"
        End With
        last2.ConnectionName =   "销售系统"
        Do
            xlh = last.ExecuteScalar()
            With last2
                .CommandText = "update {编号} set [顺序号] = " & ( xlh +1) & " where [前缀] = \'" & kfdm & "\'and [表名] = \'客户档案\' "
            End With
            If last2.ExecuteNonQuery() > 0 Then
                Exit Do
            End If
        Loop
        dr("客户简码") = kfdm & "-" & Format(xlh,"0000")
        dr("地址") = dr("所属_省市") & dr("所属_市") & dr("所属_县市")
End Select

加上下面的代码试试

If kfdmdata IsNot Nothing Then
    ……
End If