How to detect C# control name changed?

Question

I created a composite control using C# Windows Forms Control Library, when I use the new control in a test program, I want to find a way to detect when did the name of new control changed at design time, what should I do?

Answer 1

You can use the IComponentChangeService (in System.ComponentModel.Design) like in this example:

public class MyControl : UserControl
{
    public event EventHandler NameChanged;
    protected virtual void OnNameChanged()
    {
        EventHandler handler = NameChanged;
        if (handler != null) handler(this, EventArgs.Empty);
    }

    protected override void OnCreateControl()
    {
        base.OnCreateControl();

        IComponentChangeService changeService = (IComponentChangeService)GetService(typeof(IComponentChangeService));
        if (changeService == null) return; // not provided at runtime, only design mode

        changeService.ComponentChanged -= OnComponentChanged; // to avoid multiple subscriptions
        changeService.ComponentChanged += OnComponentChanged;
    }

    private void OnComponentChanged(object sender, ComponentChangedEventArgs e)
    {
        if (e.Component == this && e.Member.Name == "Name")
            OnNameChanged();            
    }
}

This service is only provided in design mode, not at runtime.
I unsubscribe and subscribe again to the ComponentChanged event (to avoid multiple subscriptions).

In the event handler OnComponentChanged I check if my name has changed and raise the NameChanged event.