C# 8 features – part 2 (async method with yield return) Microsoft promised us another great feature in C# 8 – async streams .

We now want to display all the numbers larger than a specific number. This can be handy to do stateful calculations.All of the above samples have one thing in common: they only get executed as and when necessary. The yield return statement is probably one of the most unknown features of C#.

In fact, the result is 10.

I hope this article helped explaining the semantics of the yield-keyword and the effects and implications it has on calling code.

Its behavior can seem a bit strange at first sight. It was a great experience and I wanted to share what I learned and shout out to the great professionals I met there. We’ll start with a traditional loop which returns a list:These are the steps that are executed: 1. This applies in cases such as searching and browsing a number of elements required that will be reduce the dependency on the location of the element to find. 20? However, it’s often the key to creating efficient code that is maintainable at the same time. Execution is restarted from that location the next time that the iterator function is called.You can use a yiel…

If the above method did not have deferred execution, it would mean we would:Because of deferred execution however, this can be reduced to:While maybe a contrived example, it shows clearly how deferred execution can greatly increase efficiency.Side note: I want to make clear that deferred execution in itself does not make your code faster. 3. We’ll start with a traditional loop which returns a list:At first sight, we might think that this is a function which returns a list of 5 numbers. In this week’s post I want to do the same thingLast week I attended my first Open MVP day since I got the Microsoft MVP award. A method that returns an IEnumerable and does so using yield return isn’t defining a return value–it’s defining a protocol for interacting with client code. In a traditional implementation that might look like this:While this will work, it has a disadvantage: we had to create an intermediate list to hold the items. Each iteration of the foreach loop calls the iterator method. Let’s start with an easy example:While the above has no value for anything serious, it’s a good example to debug to see how the yield return statement works.

It’s the mechanism of pause/resume in the methods that makes this possible.

Let’s see why:Because this is non-obvious behavior, tools such as Resharper will warn you about multiple iterations.It’s pretty neat that we can write seemingly infinite loops and get away with it, but what can we use it for in real life?

In the article below we will learn some programming techniques that revolve around C# yield return keywords.To use "yield return", you just need to create a method with a return type that is an IEnumerable (arrays and collections in. Because of the pause/resume behavior, the variable total will hold its value between iterations. What happens here is that each iteration of the A first use case of the yield statement is the fact that we don’t have to create an intermediate list to hold our variables, such as in the example above. Following the previously described steps, in the case of the method without yield, the loop will never finish as it will keep looping forever inside the Another side effect of the yield return statement is that multiple invocations will result in multiple iterations. Let’s take a look at the following example:The above code will output the values 1,3,6,10,15.