Question

这里有一个小问题。

我在报告中具有Switch函数，如下所示：

=Switch(

    Fields!Duration.Value > 0, Round(Fields!Duration.Value / 60),

    Fields!LastTime.Value = nothing, "Still Occupied",

    Fields!LastTime.Value = Fields!FirstTime.Value, "Passing By"

)

这是一列，以分钟为单位显示“ Fields！Duration.Value”的总数（四舍五入），除了第二行以外，它还在工作：

如果“ Last Time”值与“ First Time”值相同，则假定该对象刚刚经过并输出“ Passing By”，并且可以正确执行此操作。

但是，如果“ Last Time”值等于“ no”（在“ Last Time”列中定义，则为“ Nothing”，则为“ nothing”，并且应在此报告中输出“ Still Occupied”）单元格留空，好像我写成Fields!LastTime.Value = nothing, nothing,

为什么这行代码不起作用？

    Fields!LastTime.Value = nothing, "Still Occupied",

谢谢

Answer 1

您不能使用=运算符测试Nothing。没有什么可以测试的方法有两种：使用类似IsNothing(Fields!LastTime.Value) = True的IsNothing检查函数，或使用类似Fields!LastTime.Value Is Nothing的Is操作符。

如果这些测试未产生预期的结果，则可能是因为您处理的字段设置为NULL以外的其他值，例如empty或任意值。您可以在数据集属性上打开查询设计器以运行查询并检查结果。

您也可能正在查看数据集的错误映射。使用“数据集”属性上的“刷新字段”按钮来验证“字段映射”，然后再次检查表达式中使用的名称是否匹配。

Answer 2

I found that using an IIF statement instead of a Switch statement worked for me, at least for this specific case:

=IIF(Fields!Duration.Value > 0, Round(Fields!Duration.Value / 60),
IIF(Fields!LastTime.Value = Fields!FirstTime.Value, "Passing by", "Still Occupied"))

Going to try to explain it for future people that might not understand (like me when I eventually forget it - I am very new to this sort of stuff) -

Rather than using the Switch statement I had in place to see if Fields!LastTime.Value is a number, equal to Fields!FirstTime.Value, or nothing, it now just asks if it is a number or if it is equal to Fields!FirstTime.Value, and if neither of those are true, it marks it as "Still Occupied" thus removing the need to reference nothing entirely. Like I said, this is pretty case specific, but you never know.

Thank you for the help @JamieSee and @SuperSimmer 44. Cheers!

Answer 3

可能是“”周围没有任何东西

引用“ nothing”时，开关功能未返回正确的值

3 个答案: