Initializing C auto-properties

Question

I m used to writing classes like this   public class foo     private string mBar    bar     public string Bar       get   return mBar        set   mBar   value                other methods  no constructor         Converting Bar to an auto-property seems convenient and concise  but how can I retain the initialization without adding a constructor and putting the initialization in there   public class foo2theRevengeOfFoo       private string mBar    bar     public string Bar   get  set            other methods  no constructor         behavior has changed      You could see that adding a constructor isn t inline with the effort savings I m supposed to be getting from auto-properties   Something like this would make more sense to me   public string Bar   get  set       bar

User · Answer

You can do it via the constructor of your class:

public class foo {
  public foo(){
    Bar = "bar";
  }
  public string Bar {get;set;}
}

If you've got another constructor (ie, one that takes paramters) or a bunch of constructors you can always have this (called constructor chaining):

public class foo {
  private foo(){
    Bar = "bar";
    Baz = "baz";
  }
  public foo(int something) : this(){
    //do specialized initialization here
    Baz = string.Format("{0}Baz", something);
  }
  public string Bar {get; set;}
  public string Baz {get; set;}
}

If you always chain a call to the default constructor you can have all default property initialization set there. When chaining, the chained constructor will be called before the calling constructor so that your more specialized constructors will be able to set different defaults as applicable.

User · Answer

Update - the answer below was written before C  6 came along  In C  6 you can write  public class Foo       public string Bar   get  set       quot bar quot      You can also write read-only automatically-implemented properties  which are only writable in the constructor  but can also be given a default initial value   public class Foo       public string Bar   get         public Foo string bar                Bar   bar            It s unfortunate that there s no way of doing this right now  You have to set the value in the constructor   Using constructor chaining can help to avoid duplication   Automatically implemented properties are handy right now  but could certainly be nicer  I don t find myself wanting this sort of initialization as often as a read-only automatically implemented property which could only be set in the constructor and would be backed by a read-only field  This hasn t happened up until and including C  5  but is being planned for C  6 - both in terms of allowing initialization at the point of declaration  and allowing for read-only automatically implemented properties to be initialized in a constructor body

User · Answer

This will be possible in C  6 0   public int Y   get      2

User · Answer

In the default constructor  and any non-default ones if you have any too of course    public foo         Bar    bar       This is no less performant that your original code I believe  since this is what happens behind the scenes anyway

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