主题：[求助]这段代码执行速度很慢，请老师们指点

If e.DataCol.Name = "疾病编码"

    Dim dr As DataRow = e.DataRow

    Dim s As String = dr("疾病编码").SubString(0,1)

    Dim i As Integer = dr("疾病编码").SubString(1,2)

    If s = "A" OrElse s ="B" OrElse (s = "C" AndAlso i < 36)

        dr("疾病分类") = "传染性疾病"

    ElseIf (s = "C" AndAlso i >= 36) OrElse (s = "D" AndAlso i < 49)

        dr("疾病分类") = "肿瘤"

    End If

End If