C#7 tuple & async

c# tuples c#-7.0
Oszkar picture Oszkar · Mar 9, 2017 · Viewed 19.8k times · Source

Old format: 

private async Task<Tuple<SomeArray[], AnotherArray[], decimal>>         
GetInvoiceDetailAsync(InvoiceHead invoiceHead) { ... }

How can you do that in C#7 with new tuples format?

Answer

David Arno picture David Arno · Mar 9, 2017

Step 1: add the ValueTuple nuget package to your project.

Step 2: as Lucas says in his comment, change the syntax to:

private async Task<(SomeArray[], AnotherArray[], decimal)>GetInvoiceDetailAsync(
    InvoiceHead invoiceHead) 
{ 
    ...
    return (x, y, z); 
}

Note though that you can also then add names to those tuple items, along the lines of:

private async Task<(SomeArray[] x, AnotherArray[] y, decimal z)>GetInvoiceDetailAsync(
    InvoiceHead invoiceHead) 
{ 
    ... 
    return (x, y, z); 
}

And you can then access them as those names, rather than Item1, Item2 and Item3.

Related questions

What's the difference between System.ValueTuple and System.Tuple?

I decompiled some C# 7 libraries and saw ValueTuple generics being used. What are ValueTuples and why not Tuple instead? https://docs.microsoft.com/en-gb/dotnet/api/system.tuple https://docs.microsoft.com/en-gb/dotnet/api/system.valuetuple

Read More
When to use: Tuple vs Class c# 7.0

Before Tuples, I used to create a class and its variables then create object from this class and make that object the return type for some functions. Now with the tuples I can do the same and in c# 7.0 we …

Read More
C# 7 tuples and lambdas

With new c# 7 tuple syntax, is it possible to specify a lambda with a tuple as parameter and use unpacked values inside the lambda? Example: var list = new List<(int,int)>(); normal way to use a tuple in …

Read More