比如，城市的，参考代码

Dim dt As DataTable = DataTables("管理")
For Each dr As DataRow In dt.Select("")
    Dim pd_t As Date = dr("派单时间")
    Dim fk_t As Date = dr("反馈时间")
    Dim s As String = Format(pd_t, "mmss")
    Dim flag As Boolean = False
    If s >= "07:30" AndAlso s <= "19:00" Then
        Dim d As Date = new Date(pd_t.Year, pd_t.Month, pd_t.Day, 21, 0, 0)
        If fk_t > d Then
            flag = True
        End If
    ElseIf s > "19:00" Then
        Dim d As Date = new Date(pd_t.Year, pd_t.Month, pd_t.Day, 17, 0, 0)
        d = d.AddDays(1)
        If fk_t > d Then
            flag = True
        End If
    End If
    dr("超时任务") = flag
Next