Can you automatically pass "this" as parameter?

Question

Is there an option to automatically pass this as parameter to a function? For example, you can use [CallerMemberName] to automatically pass string name. I'm looking for exact option with this.

Example:

void PassMeThis([AutomaticThisParam] object source);

and usage:

public class SomeClass{    
    void SomeMethod(){
        PassMeThis(); // instead of PassMeThis(this)
    }
}

`PassMeThis()` and `PassMeThis(this)` would be two separate methods, though — OneCricketeer, Nov 07 '18 at 19:42
Where is located the PassMeThis method? If it is inside the same class then what is the purpose of this thing? — Steve, Nov 07 '18 at 19:43
Most likely you are looking for .NET Extension methods, as @Willie answered. Alternatively, if you want default context data that is automatically picked up by such functions in your code in a given execution context, like a thread, then there are alternatives to that as well - like ThreadStatic fields. — Ryan Pierce Williams, Nov 07 '18 at 19:55

score 5 · Accepted Answer · answered Nov 07 '18 at 19:46

5

Yes absolutely. This is called an extension Method.

Create a static class Public static class MethodExtensions
Add a static method to it like this public static PassMeThis(this SomeClass model) { // }
Call the method like this (referring to your code example): this.PassMeThis()

And it's automaticly filled. I hope thats what you were looking for

answered Nov 07 '18 at 19:46

Willie

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I think you need the Extension attribute as well (but maybe C# does this automatically for you unlike VB.NET) – Ryan Pierce Williams Nov 07 '18 at 19:50
4

@RyanPierceWilliams in VB you will need it. In C# it's automaticly clear by using the `this` keyword in the param signature – Willie Nov 07 '18 at 19:51
1

Oh! How did I not think of this? Thanks for the answer! :) – Kuker Nov 08 '18 at 12:23

score 1 · Answer 2 · answered Nov 07 '18 at 19:43

If PassMeThis is in the same class (or ancestor), as in your example, there is no point, this is avaiable there, too.

If it is in another class, there is no way to automatically get a reference to the calling object: IS there any way to get a reference to the calling object in c#?

Can you automatically pass "this" as parameter?

2 Answers2