Question

Morning all,

I’ve created a custom control with an image property. That image property is a get/set to a private Image variable.

Can anyone tell me how I enable that get/set to clear the property from the designer?

I.e. if I add an image to a standard PictureBox, I can hit Del to clear the image from the PictureBox. How can I replicate this behaviour on my own custom control?

Answer 1

At the simplest level, DefaultValueAttribute should do the job:

private Bitmap bmp; [DefaultValue(null)] public Bitmap Bar {     get { return bmp; }     set { bmp = value; } } 

For more complex scenarios, you might want to try adding a Reset method; for example:

using System; using System.Drawing; using System.Windows.Forms; class Foo {     private Bitmap bmp;     public Bitmap Bar {         get { return bmp; }         set { bmp = value; }     }     private void ResetBar() { bmp = null; }     private bool ShouldSerializeBar() { return bmp != null; } } static class Program {     [STAThread]     static void Main() {         Application.EnableVisualStyles();         Form form = new Form();         PropertyGrid grid = new PropertyGrid();         grid.Dock = DockStyle.Fill;         grid.SelectedObject = new Foo();         form.Controls.Add(grid);         Application.Run(form);     } }