Question

In C#, if you have multiple constructors, you can do something like this:

public MyClass(Guid inputId, string inputName){     // do something }  public MyClass(Guid inputId): this(inputId, 'foo') {} 

The idea is of course code reuse. However, what is the best approach when there is a bit of complex logic needed? Say I want this constructor:

public MyClass(MyOtherClass inputObject) {     Guid inputId = inputObject.ID;     MyThirdClass mc = inputObject.CreateHelper();     string inputText = mc.Text;     mc.Dispose();     // Need to call the main Constructor now with inputId and inputText  } 

The caveat here is that I need to create an object that has to be disposed after use. (Clarification: Not immediately, but I have to call Dispose() rather than waiting for Garbage Collection)

However, I did not see a way to just call the base constructor again if I add some code inside my overloaded constructor. Is there a way to call the base constructor from within an overloaded one?

Or is it possible to use

public MyClass(MyOtherClass inputObject): this(inputObject.ID,                                                inputObject.CreateHelper().Text)  {} 

Would this automatically Dispose the generated Object from CreateHelper()?

Edit: Thanks so far. Two problems: I do not control MyOtherClass and I do not have Extension Methods (only .NET 3.0…). I do control my own class though, and since I’ve just started writing it, I have no problem refactoring the constructors if there is a good approach.

Answer 1

The most common pattern used to solve this problem is to have an Initialize() method that your constructors call, but in the example you just gave, adding a static method that you called like the code below, would do the trick.

public MyClass(MyOtherClass inputObject): this(inputObject.ID, GetHelperText(inputObject) {}  private static string GetHelperText(MyOtherClass o) {    using (var helper = o.CreateHelper())       return helper.Text; }