Home / Questions / 3767
Accepted
Edwin V
Asked: 2020-02-06 15:06:25 +0800 CST 2020-02-06 15:06:25 +0800 CST

What is "=>" used for in C#

  • 772

My question is what the => characters are used for in C#, I have seen it in a method to access the device's light sensor. This is the method

private void _lightSensor_ReadingChanged(LightSensor sender, LightSensorReadingChangedEventArgs args)
    {
        _dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
        {
            Lux = args.Reading.IlluminanceInLux;
        });

        Debug.WriteLine("Lux: {0}", Lux);
    }

Thanks.

c#

3 Answers

  1. Best Answer

    In C# the operator =>is known as the lambda operator.

    It is used to create a Func<>, Action<>or Expression<Func<>>as needed.

    in your case

    () =>
    {
        Lux = args.Reading.IlluminanceInLux;
    }

    It is equivalent to a method similar to this

    void MetodoAPasarleAlRunAsync()
{
    Lux = args.Reading.IlluminanceInLux;
}

    To the left of =>it is the list of arguments, in this case empty, and to the right is the block of code to be executed.

    Since there is only a pair of empty parentheses on the left, the method has no parameters and since the code block does not return anything, its return type will bevoid

    • 7

  2. Lambda operator =>

    The token => is called the lambda operator. Used in lambda expressions to separate input variables on the left side from the lambda body on the right side. Lambda expressions are inline expressions similar to anonymous methods, but more flexible; they are used extensively in LINQ queries that are expressed in method syntax. For more information, see Lambda Expressions (C# Programming Guide).

    Operator documentation = > in Spanish.

    • 6

  3. It's a lambda expression or operator, the same thing my colleague said up there, it's part of the functional programming operators in C# and other languages, it's a shorter way of writing a function, plus it allows you to create simpler rules, that is , contributing to what has already been mentioned in this, I tell you that you can validate objects, you can declare axioms that will later be executed.

    internal static readonly Predicate<objetParaValidacion>[] Validation =
{
    (x) => x.Id != null && x.Id != "",
    (x) => x.CropId != null && x.CropId != "",
};

    So if you realize you can do that with these kind of functions, instead of using a bunch of if-elseyou can make a collection of functions that validate the state of an object. avoid spaghetti code.

    This is for you to see the potential that this type of programming has and its usefulness, however, it is just an example of everything that can be achieved using this.

    I'm not trying to explain this whole paradigm to you in a single example, that would be impossible, but I'll tell you with this example a usefulness and value that you can achieve if you learn it.

    • 0