C# 7.0 introduced local functions and with C# 8.0 one can create static local functions. Let’s have a look at what differentiates them.
Below you can find the list of all features introduced in C# 7. Tuples Deconstruction Out variables Patterns Discards Literal improvements Local functions Expression-bodied members Throw Expressions Ref returns and ref locals Generalized async return types
Before C# 7 every async method had to return Task, Task<T> or void. The new C# version extends the range of returned types.
Returning reference instead of value might be very useful – especially when one has to deal with big structures. C# allows passing parameters by reference, but a method was not able to return a reference. This has been changed with C# version 7.0.
Before C# 7.0 it was not possible to throw an exception directly in expression-bodied members. The workaround was to call a method that throws an exception.
Expression bodied members were a very popular feature of C# 6.0. Unfortunately, their usage was limited only to methods and properties.
There are situations when one needs a small helper method, but it’s not quite obvious where to put it. The method might not be generic enough to expose it as a new entity or even as a class member.
C# 7.0 introduced nice improvements to literals. Both digit separator and binary literals can improve code readability.
Sometimes there is a need to ignore a result of a method. It’s straightforward if that’s a return value – just don’t assign it. But what should be done in other cases?
The concept of patterns was introduced in C# 7.0. The idea is to check if an object reflects a specified shape.