位图不会出现在表单中

Question

I am trying to make a bitmap appear in my form, but it won't work.

my code:

private void button2_Click(object sender, EventArgs e)
{
    Graphics g = this.CreateGraphics();
    Pen pen = new Pen(Color.Black);

    Bitmap bitmap = new Bitmap(1000, 1000);
    Graphics gfx = Graphics.FromImage(bitmap);
    gfx.Clear(Color.Red);

    for (int i = 0; i < 5; i++)
    {
        gfx.DrawRectangle(pen, i + 50, 50, 50, 50);
    }
}

Answer 1

All your code is doing is drawing to a bitmap, in memory. You don't have any code to actually display that bitmap anywhere.

You could modify the code to paint the bitmap onto the form, but as nvoigt suggested in comments, a better solution would be to use a PictureBox control. When you create your bitmap, you can assign that bitmap to the picture box's Image property:

Bitmap bitmap = new Bitmap(1000, 1000);
// render bitmap

pictureBox1.Image = bitmap;

If you absolutely must draw on the form itself, you can override the form's OnPaint method, and use the graphics object's DrawImage() method to render your bitmap there.