how does the "<someType>" thing work?

I want to create a method, which returns the type defined in those brackets like so:

Code (CSharp):

1. public function T returnSomething<T>(){
2.  
3. return new T();
4. }

and T can be any type, if the Type isn't support then it will return null.
Just like the MonoBehaviour.getComponent<>() Method.

How to do this?

Edit:
hmm seems to work already, kind of...

 

If the components on a MonoBehaviour was just an list of Components, the GetComponent<T> method would look like this:

Code (csharp):

1. private List<Component> components;
2.  
3. public T GetComponent<T>() {
4.     foreach(var component in components) {
5.         if (component is T) {
6.             return (T) component;
7.         }
8.     }
9.     return null;
10. }

 

If you remove the "function" word, it is mostly correct. Your type is T, since that's your return type. You have nothing to return, so as a very simple and useless example, let's give it the thing it's supposed to return as parameter. Then it looks like this:

Code (CSharp):

1. public T Something<T>(T input){
2.     return input;
3. }

Here we give the method something of some type T, and then return something of the same type (in this case the same object we got as input). I dont think you can create a "new T()" tho, as some constructors expect parameters. If that's possible, then it's not safe, so you'd need to restrict the allowed types somehow and throw an exception if it's something else.

Generally speaking, the keyword you are looking for is "generics":
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/

 

Specifically, you'd need to add a "where" statement onto the function definition to ensure that it has the desired constructor:

Code (csharp):

1. public T Something<T>() where T : new()
2. {
3. return new T();
4. }

There are a ton of kinds of restrictions you can put into a "where" statement to ensure that the supplied class fits any needs you have to.