Understanding the meaning of this c# code

Question

I'm trying to understand the following code:

  flow = new GoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
  {
    DataStore = new FileDataStore("Tasks.ASP.NET.Sample.Store"),
    ClientSecretsStream = stream,
    Scopes = new[] { TasksService.Scope.TasksReadonly }
  });

From my understanding, the code between the first and last {...} is the body of an anonymous function. The new FileDataStore creates a new instance of FileDataStore. What I don't understand is what the comma at the end of it means. The two lines following it also have commas at the end. What kind of construct is this called in C#? I'm not familiar with it.

This is called [*Object initializer*](http://msdn.microsoft.com/en-us/library/bb384062.aspx) — Sergey Berezovskiy, Jan 08 '14 at 10:48

score 9 · Accepted Answer · answered Jan 08 '14 at 10:47

9

No, it isn't the body of an anonymous function. It is an initialization list.. and it serves to set the fields of the new object of type GoogleAuthorizationCodeFlow.Initializer all in-line.

It is the "in-line" version of this:

var initializer = new GoogleAuthorizationCodeFlow.Initializer();
initializer.DataStore = new FileDataStore("Tasks.ASP.NET.Sample.Store");
initializer.ClientSecretsStream = stream;
initializer.Scopes = new[] { TasksService.Scope.TasksReadonly };

flow = new GoogleAuthorizationCodeFlow(initializer);

The two are equivalent functionally. It is just more compact.

answered Jan 08 '14 at 10:47

Simon Whitehead

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What you wrote above is what I am more familiar with. What version of c# was this inline introduced in? Any idea? I don't recall it being in earlier versions. I actually like the longer method. Easier on the eyes :-) – Johann Jan 08 '14 at 11:02
@AndroidDev Object and collection initializers were introduced in [C# 3.0](http://msdn.microsoft.com/en-us/library/bb308966.aspx) (March 2007). – Brian Rogers Jan 09 '14 at 21:26

score 3 · Answer 2 · answered Jan 08 '14 at 10:48

It's a constructor initializer. The code is creating a new GoogleAuthorizationCodeFlow.Initializer object, and setting DataStore, ClientSecretsStream and Scopes properties on the object.

This is then being passed to a GoogleAuthorizationCodeFlow constructor as an argument.

score 0 · Answer 3 · answered Jan 08 '14 at 10:55

0

You have a class Sample.

public class Sample()
{
    public string id { get; set; }
    public int key { get; set; }
}

This can be initialized as

var sample = new Sample {id = 1, key = "one"};

Then pass this sample as argument.

In your example they have done same thing to the parameter. This is called as class initializer.

Hope it helps.

answered Jan 08 '14 at 10:55

Sandy

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Is this the same thing as a class constructor where you can have parameters in the constructor? – Johann Jan 08 '14 at 11:01
In your example `GoogleAuthorizationCodeFlow` constructor needs an instance of `GoogleAuthorizationCodeFlow.Initializer` object/class. As I see `GoogleAuthorizationCodeFlow.Initializer` has a parameter less constructor. You code snippet is creating the class instance using class initializer and passing this as a parameter. Hope it was clear now. – Sandy Jan 08 '14 at 11:59

Understanding the meaning of this c# code

3 Answers3