Question

Here’s my code:

int ypos = 0;

public void X()
{
    MovieItem NewMovie = new MovieItem();
    NewMovie.SearchMovie(txtSearch.Text);
    NewMovie.Location = new Point(0, ypos);
    ypos += 196;

    panel1.Controls.Add(NewMovie);
}

After running method X about 4,5 times, the 5th or 6th item added isn’t added where it should instead it is loaded wayyyy below.

Image for clarity:

How it looks CORRECTLY at the beginning:

How it looks WRONG after a bit:

What am I doing wrong that it doesn’t work that well?

EDIT:
I’ve used breakpoints and discovered that the problem occurs on the fifth movie, when the ypos variable is around 980. Why could this be? It just skips that location it seems.

Answer 1

ok, the problem appears when the AutoScroll property of panel is set to true and the scroll bar is not at its initial position:0. The panel is positionning the controls at ypos + vertical position of scroll bar!!

Either set AutoScroll = false; before adding MovieItem then true; after, but this will reset the scroll bar position
or, substract the scroll bar position from ypos when setting the location.

Both fix the problem but the 2nd is better (no scroll bar reset):

public void X()
{
    int vscrollPos = panel1.VerticalScroll.Value;   

    MovieItem NewMovie = new MovieItem();
    NewMovie.SearchMovie(txtSearch.Text);
    NewMovie.Location = new Point(0, ypos - vscrollPos);
    ypos += 196;

    panel1.Controls.Add(NewMovie);
}