C#•15mo ago

❔ Action and Callback

 Action<Action<int, string, bool>> configureDisplayInfo = (callback) =>
 {
     int age = 30;
     string name = "Alice";
     bool isActive = true;

     callback(age, name, isActive);
 };

 Action<int, string, bool> displayInfo = (age, name, isActive) =>
 {
     Console.WriteLine($"Name: {name}");
     Console.WriteLine($"Age: {age}");
     Console.WriteLine($"Is Active: {isActive}");
 };

 configureDisplayInfo(displayInfo);

 Action<Action<int, string, bool>> configureDisplayInfo = (callback) =>
 {
     int age = 30;
     string name = "Alice";
     bool isActive = true;

     callback(age, name, isActive);
 };

 Action<int, string, bool> displayInfo = (age, name, isActive) =>
 {
     Console.WriteLine($"Name: {name}");
     Console.WriteLine($"Age: {age}");
     Console.WriteLine($"Is Active: {isActive}");
 };

 configureDisplayInfo(displayInfo);

We are passing a function named "callback" as if it were a variable as a parameter, and then we are calling it as if we had previously called the function by saying "callback(age, ...)". How does this process work, how do the codes work step by step?

6 Replies

Angius•15mo ago

It just kinda does. In C#, like in many other languages, you can pass pointers to functions around This is no different Whether you pass an anonymous function (Action<>, Func<>, delegate) or an actual method And you don't pass it "as if it was a variable" because it is, in fact, stored in that variable Or at least the reference to it

MODiX•15mo ago

Angius

REPL Result: Success

Action<string> cwl = Console.WriteLine;
cwl("Hello world!");

Action<string> cwl = Console.WriteLine;
cwl("Hello world!");

Console Output

Hello world!

Hello world!

Compile: 645.382ms | Execution: 78.123ms | React with ❌ to remove this embed.

moonOP•15mo ago

When the function is invoked, it happened like this, right? And lastly, the relevant function became this: Instead of callback(age, name, isActive) being at runtime, it became displayInfo(age, name, isActive)

Angius•15mo ago

Like in case of any other parameter, yes

moonOP•15mo ago

Thank you a lot, I understood

Accord•15mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Action and Callback