主题：[求助]一个流水账的问题

Select Case e.DataCol.Name
    Case "收入","支出"
        For Each dr As DataRow In e.DataTable.Select("[_SortKey] >= " & e.DataRow("_SortKey"))
            Dim Val1 As Double = e.DataTable.Compute("Sum(收入)","[_SortKey] <= " & dr("_SortKey"))
            Dim Val2 As Double = e.DataTable.Compute("Sum(支出)","[_SortKey] <= " & dr("_SortKey"))
            dr("余额") = Val1 - Val2
        Next
End Select

可是上面在支出6608.3的时候余额就不对了，其他都是正确的，请问老师这个怎么破？