C# constructor execution order

The order is:

• Member variables are initialized to default values for all classes in the hierarchy

Then starting with the most derived class:

• Variable initializers are executed for the most-derived type
• Constructor chaining works out which base class constructor is going to be called
• The base class is initialized (recurse all of this :)
• The constructor bodies in the chain in this class are executed (note that there can be more than one if they're chained with Foo() : this(...) etc

Note that in Java, the base class is initialized before variable initializers are run. If you ever port any code, this is an important difference to know about :)

I have a page with more details if you're interested.

It will call the base constructor first. Also keep in mind that if you don't put the :base(param1) after your constructor, the base's empty constructor will be called.

The constructor of the baseclass is called first.