[c#] Initializing C# auto-properties

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";

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.

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.

This will be possible in C# 6.0:

public int Y { get; } = 2;