Question

Should I dispose GDI+ object before its creation?

Is recommended to always Dispose GDI+ object after using it.

by e.g.

Pen p = new Pen(Color.Green);
// use 'p'
p.Dispose();

now, if I have this situation:

Pen p = new Pen(Color.Green);
// use green 'p'

p = new Pen(Color.Red); // Should I Dispose my 'p' first?
// use red 'p'

p.Dispose();

EDIT A:

Using ‘USING’ is not possible every time.

private Pen p;

public RefreshPen(style)
{
    // p.Dispose(); +-
    p = new Pen(style.Color);
    // etc.
}

EDIT B:

Will this be OK?

using (Pen p = new Pen(Color.Green))
{
    // use green 'p'

    p = new Pen(Color.Red); // Should I Dispose my 'p' first?
    // use red 'p'

    p = new Pen(Color.Blue); // Should I Dispose my 'p' first?
    // use blue 'p'
}

Answer 1

Yes, you should. (Also note that the using statement is a tremendous help here. I very rarely call .Dispose explicitly. using takes care of that.)