第三没看懂
第一、二参考,表C,datacolchanged事件,建议把列改为整数型,不然超出2位数取最大值会有问题
If e.DataCol.Name = "类型"
Dim dr As DataRow = DataTables("表A").Find("","RIQI desc")
If dr IsNot Nothing
For Each dc As DataCol In e.DataTable.DataCols
If dc.Name.Length = 4
Dim v As String = DataTables("表A").Compute("max(" & dc.Name & ")")
Select Case e.NewValue
Case "每列最大数"
e.DataRow(dc.Name) = v
Case "最大数减最新数据"
e.DataRow(dc.Name) = val(v) - val(dr(dc.Name))
End Select
End If
Next
End If
End If