C# - Adding to an existing (generated) constructor

Question

I have a constructor that is in generated code. I don't want to change the generated code (cause it would get overwritten when I regenerate), but I need to add some functionality to the constructor.

Here is some example code:

// Generated file
public partial class MyGeneratedClass
{
   public MyGeneratedClass() 
   {
      Does some generated stuff
   }
}

The only solution I can come up with is this:

// My hand made file
public partial class MyGeneratedClass
{
   public MyGeneratedClass(bool useOtherConstructor):this()
   {
      do my added functinallity
   }
}

I am fairly sure this will work, but I then have a lame unused param to my constructors and I have to go change them all. Is there a better way? If not that is fine, but I thought I would ask.

Answer 1

If you're using C# 3 and can change the generator, you can use partial methods:

// MyGeneratedClass.Generated.cs
public partial class MyGeneratedClass
{
   public MyGeneratedClass() 
   {
      // Does some generated stuff
      OnConstructorEnd();
   }

   partial void OnConstructorEnd();
}

// MyGeneratedClass.cs
public partial class MyGeneratedClass
{
   partial void OnConstructorEnd()
   {
      // Do stuff here
   }
}

Answer 2

Would your environment allow you to inherit from MyGeneratedClass rather than have it as a partial class. You could then override the constructor?

Answer 3

Assuming you can't change the generator output, unfortunately, your options are a bit limited, and not ideal considering what you're looking for. They are:

• Inherit from the generated class. The child class will implicitly call the parent's construtor.
• Use a static method as an initializer