How do I remove the bitmap from a custom control in WinForms?

Question

I have a form that is loaded with a generated bitmap. I want the user to be able to press a button and change the graphic displayed. My question is, how can I delete the bitmap that is currently displayed?

Edit: The bitmap is loading onto an ImageBox (not directly onto the form) Which was kindly suggested by Hans Passant c# panel for drawing graphics and scrolling

Thanks

score 2 · Accepted Answer · edited May 23 '17 at 12:26

Same principle as leppie's answer. Except that you need to set the ImageBox.Image property instead:

myImageBox.Image = null;

This works because of the following code (excerpted from Hans's answer to your previous question):

protected override void OnPaint(PaintEventArgs e) {
    e.Graphics.TranslateTransform(this.AutoScrollPosition.X, this.AutoScrollPosition.Y);
    if (mImage != null) e.Graphics.DrawImage(mImage, 0, 0);
    base.OnPaint(e);
}

When you set the control's Image property to null, the property setter forces the control to repaint itself (this.Invalidate();). When it repaints itself, no image is drawn because the OnPaint method that is responsible for painting the control verifies that mImage != null before drawing it.

score 1 · Answer 2 · answered Jan 12 '11 at 10:22

1

The following should work:

Form.BackgroundImage = null;

answered Jan 12 '11 at 10:22

leppie

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Hi, unfortunately this doesn't work as the bitmap is not loaded directly to the form. Please see my edit above. Thanks. – Darren Young Jan 12 '11 at 10:32

How do I remove the bitmap from a custom control in WinForms?

2 Answers2