Question

I am designing a simple picture viewer with ability to do some basic image processing. At the moment I have the problem of keeping the PictureBox centered inside a TabPage all the time as well as keeping the picturebox width and size same as the picture its showing. So far I had no success.

I have the following code that I call in form constructor to position it in center. it works the first time to center the picturebox:

private void SetPictureBoxOriginalSizeAndLocation(bool makeImageNull = false, DockStyle dockStyle = DockStyle.None)
{
    if (makeImageNull) picBoxView.Image = null;
    picBoxView.Dock = dockStyle;

    var xPoint = tabImageView.Location.X + ((splitContainer.Panel2.Width / 2) / 2);
    var yPoint = tabImageView.Location.Y;

    var width = tabImageView.Width / 2;
    var height = (tabImageView.Height / 2) - toolStripImageView.Height;

    if (picBoxView.Image == null) return;

    //Resize image according to width
    picBoxView.Image = ImageMethods.ResizeImage(picBoxView.Image.Tag.ToString(), width, height, false); 

    picBoxView.Location = new Point(xPoint, yPoint);
    picBoxView.Width = width;
    picBoxView.Height = height;
}

But it does not resize the picturebox to its image (you can see the black part that is back color for the picturebox control):

The problem is getting worse as soon as I resize the form, the picturebox position will goes to top:

I call the code above in form’s resize event as well, no idea why it works when application starts. Would be nice if someone can tell me what properties I should take care of to achieve a nicely centered picturebox which always is as big as its image.

Answer 1

It’s pretty easy if you just set the Anchor style to none:

picBoxView = new PictureBox();
picBoxView.SizeMode = PictureBoxSizeMode.AutoSize;
picBoxView.Anchor = AnchorStyles.None;
tabImageView.Controls.Add(picBoxView);
CenterPictureBox(picBoxView, myImage);

Then just center the PictureBox initially whenever you change the image of the PictureBox:

private void CenterPictureBox(PictureBox picBox, Bitmap picImage) {
  picBox.Image = picImage;
  picBox.Location = new Point((picBox.Parent.ClientSize.Width / 2) - (picImage.Width / 2),
                              (picBox.Parent.ClientSize.Height / 2) - (picImage.Height / 2));
  picBox.Refresh();
}

Having the Anchor = None will center the PictureBox control for you whenever the parent container gets resized because it “isn’t” anchored to the default Left and Top locations.