这种从 vb.net 中的 function 返回多个值的技术的名称是什么？

Question

Protected Function ammountChanges(order As BasicSimpleOrder, createOrDelete As Boolean) As (change As Decimal, currency As String)


End Function

I sort of know that it's possible and I want to learn more about it.

However, if I search in google for

function returning multiple values vb.net

for example,

or in stackoverflow

no body is mentioning that technique.

Even if I search for

function returning multiple values through anonymous type 

people are still using different techniques.

Now I think it's a new feature.

Basically, you "can't" really return multiple values. You can return a class or a struct and that class or struct can contain multiple values.

However, recent vb.net improvement allow a convenient way to allow an anonymous type as return values.

However, I cannot find any reference to that method anywhere on the.net. Not easily. Not with the keyword I found.

So where is it, and what should I search in google to learn more about this feature.

Answer 1

It's Tuples introduced in Visual Basic 15 / Visual Studio 2017 .

See the section: Tuples as method return values where it mentions (with code examples):

A method can return only a single value. Frequently, though, you'd like a method call to return multiple values. There are several ways to work around this limitation:

• You can create a custom class or structure whose properties or fields represent values returned by the method. This is a heavyweight solution; it requires that you define a custom type whose only purpose is to retrieve values from a method call.

• You can return a single value from the method, and return the remaining values by passing them by reference to the method. This involves the overhead of instantiating a variable and risks inadvertently overwriting the value of the variable that you pass by reference.

• You can use a tuple , which provides a lightweight solution to retrieving multiple return values .