Update
As in C # 6 (VS2015), this syntax is perfectly correct
public bool Value { get; set; } = true;
as sets the readonly property
public bool Value { get; } = true;
Old pre C # 6 answer
Exciting spoiler warning: The following code will not work
You ask: "Can I do this?"
public bool Value { get; set; } = true;
No, you canβt. You need to set the default value in the class constructor