Function that takes another function as a parameter in C#

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4

In the language Lua has how to create a function that takes as argument another function, for example :

exemplo = function(outrafunction)
  outrafunction()
end

exemplo(function print("alguma coisa") end)

Is there any way to do it using C#?

c# function lua anonymous-function

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3 answers

5

Your syntax is wrong, but okay.

In C# would be:

using System;
using static System.Console;

public class Program {
    public static void Main() => Exemplo(() => WriteLine("alguma coisa"));
    public static void Exemplo(Action outraFunction) => outraFunction();
}

Behold working in the ideone. And in the .NET Fiddle. Also put on the Github for future reference.

It’s essentially a different syntax, but the mechanism is identical.

0

Is it possible that this action is of the bool type ? Every time I try to make that change : "private void BuscarComprasASSD(string conta, Action Buscar, Action<bool> condicao )"

This error appears:

 não há argumento fornecido que corresponde ao parâmetro formal necessário "obj" de Action<bool>

0

If you want a function to be passed by parameter in a simple way use Action or Func. The difference between the two is that Action is void type. With Func you can have a Return type, and up to 16 input parameters. In the following example I used an Action and an Func to invoke a function but if the function can return a value.

If you want to have a wider view you can see how the delegates.

 public static void Main()
{
  Exemplo(() =>  IsLeapYear());
  Exemplo2(() => IsLeapYear());
  bool x = Exemplo3(()=> IsLeapYear());
  bool y = Exemplo3(() => IsLeapYear( DateTime.Now.Year));
}

public static void Exemplo(Action outraFuncao) => outraFuncao();
public static void Exemplo2(Func<bool> outraFuncao) => outraFuncao();
public static bool Exemplo3(Func<bool> outraFuncao) => outraFuncao();


private static bool IsLeapYear() => DateTime.IsLeapYear(DateTime.Now.Year);
private static bool IsLeapYear(int year) => DateTime.IsLeapYear(year);

You can still see this answer that explains functions and actions.

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