CODEWITHSUNDEEP
c#classconstructor
Victor
Victor

Reputation: 14573

Custom constructors for classes

I saw this code:

this.CreateGraphics().DrawRectangle( Pens.Black, new Rectangle( 0, 0, 200, 100 ) );

CreateGraphics() is a method, but it acts like a class with static voids. How can I create this in my code? I don't know how this technique can be called...

Upvotes: 0

Views: 1059

Answers (2)

Zbigniew
Zbigniew

Reputation: 27584

This is called Factory Method (it's one of design patterns). Basically you create a method which will return new instances of class e.g.:

public class Graphics 
{
    public static Graphics CreateGraphics()
    {
        return new Graphics();
    }

    // ... other methods etc ...
    public bool OtherMethod()
    {
        return false;
    }
}
// then you can do Graphics.CreateGraphics().OtherMethod();

UPDATE

You can use this design patter in other places, all you need to do is to create a method which will return new instance of class (CreateGraphics method):

public class MyClass 
{
    public static Graphics CreateGraphics()
    {
        return new Graphics();
    }

    // ... other methods etc ...
    public void MyOtherMethod()
    {
        this.CreateGraphics().Something();
    }
}

Upvotes: 2

Justin Harvey
Justin Harvey

Reputation: 14672

CreateGraphics() is returning an instance of the Graphics class.

I suspect you are talking about the Control.CreateGraphics() method,

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.creategraphics.aspx

Any method that returns an instance of an object like this, can be used in this way.

Upvotes: 0

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