[2.0] UserControlLibrary Default Event Handler

[Fromethius]

How can you choose which event comes up by default when a control is double clicked? My user control contains one TextBox. When I import the user control into another project and double click it, the Load event comes up by default. Would it be possible to make it TextChanged by default instead?

[jmcilhinney]

You need to apply the DefaultEvent attribute to your class, e.g.

[System.ComponentModel.DefaultEvent("TextChanged")]
public partial class UserControl1 : UserControl
{
	public UserControl1()
	{
		InitializeComponent();
	}
}

[Fromethius]

Gracias. I shall give it a try. And while we're at it, how do I create default properties? I have a public property in public user control and I set it to false in the designers file, or in the declaration. Either way, when I import the control and create an instance of it, the public property is bold. For other properties, their default value is always just normal text and when you change them, THEN the text is bold, but for some reason, even when I first create the instance of it, the font is already bold as if it was changed.

Does this even matter? Honestly? No. I just want my control to look and feel like other controls made by Microsoft and other components and such. Also, the way it is shown bold before it is changed leads me to believe that quite possibly I'm doing something wrong.

[RobDog888]

Use the attributes on the property.
If you specify the default value and of correct type it will not be bolded unless its changed from that value.

Option Explicit On
Option Strict On

Imports System.Runtime.InteropServices
Imports System.ComponentModel
Imports System.ComponentModel.Design

Public Class UserControl1

	Private _ShowMenuBar As Boolean

	<Browsable(True), Category("SomeCategory"), DefaultValue(True)> _
	Public Property ShowMenuBar() As Boolean
		Get
			Return _ShowMenuBar
		End Get
		Set(ByVal Value As Boolean)
			_ShowMenuBar = Value
		End Set
	End Property
End Class

[jmcilhinney]

Apply the DefaultValue attribute to your property. That also gives you the ability to right-click it in the designer and select Reset.

Remember, if you want to control the design-time behaviour of a type or member then you're almost certainly talking about attributes.

[Fromethius]

Alright. I don't really know much at all about attributes. Got any good tutorials for learning about them?

[RobDog888]

Just check out the intellisense and see whats available. There isnt too much too them.

[RobDog888]

Ok, here is the C# for you.

using System.Runtime.InteropServices;
using System.ComponentModel;
using System.ComponentModel.Design;

public class UserControl1
{

	private bool _ShowMenuBar;

	[Browsable(true), Category("SomeCategory"), DefaultValue(true)]
	public bool ShowMenuBar
	{
		get
		{
			return _ShowMenuBar;
		}
		set
		{
			_ShowMenuBar = value;
		}
	}
}

[jmcilhinney]

Go to the MSDN Library documentation for the Attribute class, read, go to the Inheritance Hierarchy section, click on the Derived Classes link, read about each one. It's all those in the System.ComponentModel namespace that control design-time behaviour.