Cancel Click In Inherited User Control

[rich_wenger]

Hi, I've got a custom user control using inheritance that I'm working on that I would like to cancel the 'Click' event. Any help would be greatly appreciated.

[Curtis Schlak]

From the MSDN documentation on the Control.OnClick method:

The OnClick method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class. Notes to Inheritors: When overriding OnClick in a derived class, be sure to call the base class's OnClick method so that registered delegates receive the event.

From reading this, I infer that if you override your inherited control's OnClick method and do not call base.OnClick, then any registerd event handlers will not receive the event notification. The code below shows this:

using System;
using System.Windows.Forms;

namespace OnClickOverride
{
public class MainForm : Form
{
public MainForm()
{
Height = 100;
Width = 200;
Button b = new Button();
b.Text = "Normal";
b.Top = 10;
b.Left = 10;
b.Click += new EventHandler( normal_Click );
Controls.Add( b );
b = new OverriddenButton();
b.Text = "Abnormal";
b.Top = 10;
b.Left = 100;
b.Click += new EventHandler( abnormal_Click );
Controls.Add( b );
}

	private void normal\_Click( object sender, EventArgs e )
	{
		MessageBox.Show( "Clicked the normal button." );
	}

	private void abnormal\_Click(object sender, EventArgs e)
	{
		MessageBox.Show( "Clicked the abnormal button." );
	}

	\[STAThread\]
	public static void Main()
	{
		Application.Run( new MainForm() );
	}
}

public class OverriddenButton : Button
{
	protected override void OnClick(EventArgs e)
	{
		// Nothing happens.
	}
}

}

"we must lose precision to make significant
statements about complex systems."
-deKorvin on uncertainty

[rich_wenger]

Thanks for your reply; I'm trying to work it out in context.

[rich_wenger]

Hi, I'm not certain how to use this in a user control? Someone suggested I use this: protected override void onclick(System.EventArgs e) { //base.onclick (e); } But it returned an error saying "no suitable method found to override". I'm trying to interrupt the event in the user control and not in the parent form.

[Curtis Schlak]

Two things, really. 1) Does the user control inherit from the System.Windows.Forms.Control class? 2) I'm sorry, but the formatter messed up my code. The method has a capital O and capital E so that it reads OnClick.

"we must lose precision to make significant
statements about complex systems."
-deKorvin on uncertainty

[rich_wenger]

using System; using System.Collections; using System.ComponentModel; using System.Drawing; using System.Data; using System.Windows.Forms; namespace RadioButtonRocLib { public class RadioButtonRoc : System.Windows.Forms.RadioButton { private System.ComponentModel.Container components = null; public RadioButtonRoc() { Code continues.........

[rich_wenger]

This following builds but I see no effect in my test form: protected override void OnClick(System.EventArgs e) { base.OnClick(e); } -- modified at 16:01 Monday 14th November, 2005

[Curtis Schlak]

If you don't want the radio button to process the OnClic****k event, remove the base.OnClic****k(e) call from your code.

"we must lose precision to make significant
statements about complex systems."
-deKorvin on uncertainty

[Lost User]

make it like this protected override void OnClick(System.EventArgs e) { //base.OnClick(e); }

[rich_wenger]

Hi Josh, I think the Code Project site has reformatted your code or else it's identical previous suggestions.