Static constructors: used for initialising static members.
Private constructors: used when you only want a class to be instantiated from within its own code (typically in a static method). For example:
public class Thing
{
static int Number;
static Thing()
{
Number = 42; // This will only be called once, no matter how many instances of the class are created
}
// This method is the only means for external code to get a new Thing
public static Thing GetNewThing()
{
return new Thing();
}
// This constructor can only be called from within the class.
private Thing()
{
}
}