Cannot read Bitmap file using C#

Question

i'm trying to read a bitmap file with the following code:

public void open(object o, EventArgs e)
    {
        fileOpenen.Filter = "Pictures (.BMP/.JPG/.GIF/.PNG)|*.bmp;*.jpg;*.gif;*.png";
        if (fileOpenen.ShowDialog() == DialogResult.OK)
        {
          Bitmap open = new Bitmap(fileOpenen.FileName);
            schets.bitmap = open;
            this.nieuw(o, e);
    }

It should load the bitmap into "schets", which consists of the following code:

class Schets
{
    public Bitmap bitmap; // private naar public

    public Schets()
    {
        bitmap = new Bitmap(1, 1);
    }
    public Graphics BitmapGraphics
    {
        get { return Graphics.FromImage(bitmap); }
    }
    public void VeranderAfmeting(Size sz)
    {
        if (sz.Width > bitmap.Size.Width || sz.Height > bitmap.Size.Height)
        {
            Bitmap nieuw = new Bitmap( Math.Max(sz.Width,  bitmap.Size.Width)
                                     , Math.Max(sz.Height, bitmap.Size.Height)
                                     );
            Graphics gr = Graphics.FromImage(nieuw);
            gr.FillRectangle(Brushes.White, 0, 0, sz.Width, sz.Height);
            gr.DrawImage(bitmap, 0, 0);
            bitmap = nieuw;
        }
    }
    public void Teken(Graphics gr)
    {
        gr.DrawImage(bitmap, 0, 0);
    }
}

I can select a .bmp file from my hard drive but when i try to load it I get the following error: An unhandled exception of type 'System.NullReferenceException' occurred in Schets.exe

You need to look at where the error is occurring. I suspect the problem lies at `this.nieuw(o, e);` or another line. — Kami, Oct 23 '14 at 12:52
Where *does* the exception occur? Did you try debugging the code? — Panagiotis Kanavos, Oct 23 '14 at 12:54

score 1 · Answer 1 · answered Oct 23 '14 at 12:52

1

From the strack trace you can see exactly where the 'System.NullReferenceException' ocucure. Than it point to line where you try access not yet initialized object. Simply initialize the object and it will work.

answered Oct 23 '14 at 12:52

Aik

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Cannot read Bitmap file using C#

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