[API Proposal] Ability to set the default icon for Forms.

Is your feature request related to a problem? Please describe

Currently the only way to set the default icon is via reflection. This is risky as it is looking at the internals of the object. It would be best to expose an API to set it.

Example of a way to set the icon currently:

typeof(Form).GetField("defaultIcon", BindingFlags.NonPublic | BindingFlags.Static).SetValue(null, SystemIcons.Shield);

Describe the solution you’d like and alternatives you’ve considered

namespace System.Windows.Forms;

public class Form
{
    /// <summary>
    ///  Gets / sets the default icon used for a <see cref="System.Windows.Forms.Form"/>.
    /// </summary>
    /// <exception cref="System.ArgumentNullException">value is null.</exception>
    public static System.Drawing.Icon DefaultIcon { get; set; }
}

Will this feature affect UI controls?

Designer should not have to change for this. It should not impact accessibility. It should not need to be localized.

[RussKie]

I’m not sure I fully understand the business need behind this request. A form’s icon can be set via the Icon property. The DefaultIcon is an implementation detail that ensures there’s a default icon set. I would also struggle to buy in to a “we have tens/hundreds of forms in which we need to set Icon property over and over” situation - as it would denote architectural issues with the application.

[JeremyKuhne]

I didn’t consider the fact that there are multiple sizes needed for Form. (WM_SETICON)

There is a presumption that Icon is going to have all of the size data in it. You’ll get undesirable results when extracting a given HICON to create Icon.

I’m not sure the best way to handle this. Going to sit on this for a bit while I think about various options.