主题：条码的有效检验

For Each dr As DataRow In DataTables("表A").datarows
    Dim fdr As DataRow = dr.DataTable.find("a列条码 = '" & dr("b列条码") & "'")
    If fdr IsNot Nothing Then
        dr("检查B列当中有哪些是A列没有的") = Nothing
    Else
        dr("检查B列当中有哪些是A列没有的") = dr("b列条码")
    End If
Next

For Each dr As DataRow In DataTables("表A").datarows
    Dim count As Integer = dr.DataTable.compute("count(_Identify)", "a列条码 = '" & dr("a列条码") & "'")
    If count <= 1 Then
        dr("检验A列条码是否重复") = Nothing
    Else
        dr("检验A列条码是否重复") = count
    End If
Next