C# Forms Picturebox to show a solid color instead of an image

Question

Im making a little app to display the pictures of guests as they scan their cards. But i want to to display blank green or red (green if the guest exists without a photo and red if they dont exist)

But i cant figure out how to create a blank colour image.

Bitmap bmRed = new Bitmap(imgbox.Width, imgbox.Height, PixelFormat.Format24bppRgb);
imgbox.Image = bmRed;

Thats the code i have at the moment and it just makes the box black. imgbox is a PictureBox

Answer 1

Don't use an image - set the BackColor property of the PictureBox:

imgBox.BackColor = Color.Red;

Answer 2

To prevent null pointer exception, create a blank bmp

myPicBox.Image = new Bitmap(myPicBox.Width, myPicBox.Height);
Graphics graphics = Graphics.FromImage(myPicBox.Image);

Brush brush = new SolidBrush(Color.Gray);

graphics.FillRectangle(brush, new System.Drawing.Rectangle(0, 0, myPicBox.Width, myPicBox.Height));