Change Default Winform Icon Across Entire App

Question

Can I change the default icon used on a Winform?

Most of my forms have their icon property set to a custom icon. For the few forms that slip through the cracks, I d

Answer 1

The default icon is embedded in the winforms dll - looking at reflector (DefaultIcon) it is:

defaultIcon = new Icon(typeof(Form), "wfc.ico");

There is no magic in there that checks another common location, so you can't do it without changing code.

You could always embrace the forces of darkness with field-based reflection? Note: this is hacky and brittle. On your own head! But it works:

[STAThread]
static void Main() {
    // pure evil
    typeof(Form).GetField("defaultIcon",
            BindingFlags.NonPublic | BindingFlags.Static)
        .SetValue(null, SystemIcons.Shield);

    // all forms now default to a shield
    using (Form form = new Form()) {
        Application.Run(form);
    }
}

To do it properly; two common options;

• a base Form class which has the icon set
• a factory Form method - perhaps something like:

code:

public static T CreateForm() where T : Form, new() {
    T frm = new T();
    frm.Icon = ...
    // any other common code
    return frm;
}

Then instead of:

using(var frm = new MySpecificForm()) {
    // common init code
}

Something like:

using(var frm = Utils.CreateForm()) {

}

Of course - that isn't much prettier! Another option might be a C# 3.0 extension method, perhaps as a fluent API:

public static T CommonInit(this T form) where T : Form {
    if(form != null) {
        form.Icon = ...
        //etc
    }
    return form;
}

and

using(var frm = new MySpecificForm().CommonInit()) {
    // ready to use
}

This is then just a .CommonInit() away from your existing code.