CODEWITHSUNDEEP
c#winformsdrawing
Stavros Afxentis
Stavros Afxentis

Reputation: 449

Draw line on a dynamically created picturebox

i need to draw a line for example, in a dynamically created PictureBox. What happens is that the picture box is created and shown in the form but the line is missing. My code is below, any ideas?? thnx

public void create_pb()
{
    PictureBox pb = new PictureBox();
    pb.Size = new Size(200, 200);
    pb.BorderStyle = BorderStyle.Fixed3D;
    pb.Location = new Point(0,0);
    panel1.Controls.Add(pb);
    g = pb.CreateGraphics();
    Pen p = new Pen(Color.Black, 2);

    g.DrawLine(p, 0, 0, 200, 200);           
}

g is defined as public Graphics g;

Upvotes: 2

Views: 1414

Answers (1)

Blorgbeard
Blorgbeard

Reputation: 103555

Don't use CreateGraphics. You need to do your drawing in the Paint event handler instead, using e.Graphics from the event arguments passed to you.

Otherwise your line will simply be erased when the picture box is next repainted (e.g. when the form is moved, resized, covered by another form, etc).

Example:

pb.Paint += (sender, e) =>
{
    Pen p = new Pen(Color.Black, 2);
    e.Graphics.DrawLine(p, 0, 0, 200, 200);
};

Upvotes: 2

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