Question

I have problem with List<Image>

    List<Image> _Images = new List<Image>();
    int currIndex = 0;

    private void btnAdd_Click(object sender, EventArgs e)
    {
        using (OpenFileDialog dialog = new OpenFileDialog())
        {
            dialog.Filter = "All Images|*.jpg;*.jpeg;*.png;*.bmp;*.gif";
            if (dialog.ShowDialog() == DialogResult.Cancel) 
                return;
            _Images.Add(Image.FromFile(dialog.FileName));
            currIndex = _Images.Count - 1;
            picBox.Image = _Images[currIndex];
        }
    }

    private void btnNext_Click(object sender, EventArgs e)
    {
        if (currIndex + 1 >= _Images.Count)
            return;
        picBox.Image = _Images[++currIndex];
    }

    private void btnBack_Click(object sender, EventArgs e)
    {
        if (currIndex - 1 < 0)
            return;
        picBox.Image = _Images[--currIndex]; 
    }

After i added two images to that list, i got this exception when i press on Back button btnBack_Click : Parameter is not valid.
why did it work when i first add the image picBox.Image = _Images[currIndex]; then when i try to get an image from index later, it gives me that exception?

Note: i didn’t use ImageList, because as i know, it has ImageSize which will be constant for all images.

so how would i get it work?

Update :

It worked now, when i changed List<Image> to List<Stream>

picBox.Image = Image.FromStream(_Images[--currIndex]); 

Answer 1

Change your List<Image> to List<Stream>

picBox.Image = Image.FromStream(_Images[--currIndex]);

Then it will work.