CODEWITHSUNDEEP
c#
chronodekar
chronodekar

Reputation: 2746

What does <T> represent in C# syntax?

What does the following syntax mean? Specifically the <> braces? (Can't seem to google it)

public T Execute<T>(RestRequest request) where T : new()
{ .... }

Here's what I understand;

public = the visibility of the function.

T = the return type (probably defined somewhere else in code)

(RestRequest request) = the function parameter list. request is the lone parameter

The remaining bits - Execute<T> ... where T : new() is strange and new to me.

Possibly related, but what does the following actually return? (as in; does it return a function or an object or a reference to something?)

return Execute<Call>(request);

Both the code snippets were taken from the RestSharp documentation wiki example code - https://github.com/restsharp/RestSharp/wiki/Recommended-Usage

Upvotes: 1

Views: 5109

Answers (4)

arin1405
arin1405

Reputation: 677

Here it is a constraint on the generic parameter. Generic classes and methods combine reusability, type safety and efficiency. The new constraint specifies that any type argument in a generic class declaration must have a public parameterless constructor. To use the new constraint, the type cannot be abstract.

http://msdn.microsoft.com/en-us/library/0x6a29h6.aspx

http://msdn.microsoft.com/en-us/library/sd2w2ew5.aspx

Upvotes: 0

Pradeep Kesharwani
Pradeep Kesharwani

Reputation: 1478

Here represents type of your collection it could be predefined datatype or user defined datatype like any class

Upvotes: 0

MarcinJuraszek
MarcinJuraszek

Reputation: 125620

The remaining bits - Execute<T> ... where T : new() is strange and new to me.

So, Execute is method name. <T> is generic parameter T (See Generics (C# Programming Guide)) and where T : new() is generic constraint, which requires T to have parameterless constructor.

Possibly related, but what does the following actually return? (as in; does it return a function or an object or a reference to something?)

return Execute<Call>(request);

Because Execute<T> returns T and you call is with T = Call this one will return Call class instance (or possible null if only Call is class, not struct).

Upvotes: 2

Scott Chamberlain
Scott Chamberlain

Reputation: 127543

T = the return type (probably defined somewhere else in code)

Actually it is defined between the <>. When you go to call this function you put your own type in the brackets, so in your return Execute<Call>(request); turns in to the function signature public Call Execute(RestRequest request);

The where T : new() is a limitation on what you can put inside the brackets, what you are declaring is whatever is going to be passed in as T must implment a default constructor that is public (that is what new() means.

Upvotes: 2

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