C# call by value/ref + extension methods

Vote count:

0

public static class RectangleExtension
{
    public static Rectangle Offseted(this Rectangle rect, int x, int y)
    {
        rect.X += x;
        rect.Y += y;
        return rect;
    }
}


....

public void foo()
{
    Rectangle rect;

    rect = new Rectangle(0, 0, 20, 20);
    Console.WriteLine("1: " + rect.X + "; " + rect.Y);

    rect.Offseted(50, 50);  
    Console.WriteLine("2: " + rect.X + "; " + rect.Y);

    rect = rect.Offseted(50, 50); 
    Console.WriteLine("3: " + rect.X + "; " + rect.Y);
}

Output:

1: 0; 0

2: 0; 0

3: 50; 50

What I expected:

1: 0; 0

2: 50; 50

why does rect.Offseted(50, 50) not modify the x and y of the rectangle in step 2?

asked 34 secs ago

user2168711

29