C# Discussion Boards - CodeProject

14-Nov-05 4:55

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.14-Nov-05 5:26

14-Nov-05 5:26

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_wenger14-Nov-05 5:42

14-Nov-05 5:42

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

rich_wenger14-Nov-05 8:52

14-Nov-05 8:52

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.14-Nov-05 9:04

14-Nov-05 9:04

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_wenger14-Nov-05 9:48

14-Nov-05 9:48

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_wenger14-Nov-05 9:58

14-Nov-05 9:58

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.14-Nov-05 11:46

14-Nov-05 11:46

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

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

User 58385214-Nov-05 19:14

User 583852

14-Nov-05 19:14

make it like this

protected override void OnClick(System.EventArgs e)
{
//base.OnClick(e);
}

rich_wenger15-Nov-05 2:10

Converting a relative path into an absolute one

15-Nov-05 2:10

Hi Josh,

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

ListView Sorting

x-trate14-Nov-05 4:14

x-trate

14-Nov-05 4:14

Hi,
I have a listview (property View is "Details"). I set the sorting property true. Is it possible that the sorting is made after the second column and not the first one (like it does now)?
Thanks!

Re: ListView Sorting

Luis Alonso Ramos14-Nov-05 8:11

Luis Alonso Ramos

14-Nov-05 8:11

Yes, it's possible. But it's not easy. You have to handle the ColumnClick event of the ListView, provide you own sorting mechanism...

But wait, actually it's easy Smile | :)

Simply use the ListViewSortManager class from the following article:

http://www.codeproject.com/cs/miscctrl/lvsortmanager.asp[^]

I hope it helps!

-- LuisR

Luis Alonso Ramos
Intelectix - Chihuahua, Mexico

Not much here: My CP Blog!

The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005

System Dialogs

palomo9214-Nov-05 3:52

palomo92

14-Nov-05 3:52

hi all,
I would want to allow the opening of particular system dialog from my c# application. I heave find this article written in mfc/c++, is possible to written a similar class in c# ? I have tried but my solution not allow to open a system dialog as modal.

this is my class:

using System;<br />
using System.IO;<br />
using System.Diagnostics;<br />
using System.ComponentModel;<br />
using System.Windows.Forms;<br />
using System.Runtime.InteropServices;<br />
<br />
namespace System<br />
{<br />
	public class SystemDialogs<br />
	{<br />
		public SystemDialogs()<br />
		{<br />
<br />
		}<br />
<br />
		public enum Dialogs<br />
		{<br />
			SD_FORMAT               = 1,<br />
			SD_INTERNET_OPTIONS		= 2,<br />
			SD_ADD_REMOVE_PROGRAMS	= 3,<br />
			SD_DATE_TIME			= 4,<br />
			SD_DISPLAY				= 5,<br />
			SD_MODEM				= 6,<br />
			SD_MULTIMEDIA			= 7,<br />
			SD_MOUSE                = 8,<br />
			SD_NETWORK              = 9,<br />
			SD_PASSWORD             = 10,<br />
			SD_SYSTEM               = 11,<br />
			SD_REGIONAL_SETTINGS    = 12,<br />
			SD_SOUNDS               = 13,<br />
			SD_GAME_CONTROLLERS     = 14,<br />
			SD_KEYBOARD             = 15,<br />
			SD_DEVICE_MANAGER       = 16,<br />
		}<br />
		<br />
		public static void ShowDialog(SystemDialogs.Dialogs Dialog)<br />
		{<br />
			string[] Args = new string[16]<br />
			{<br />
				"Shell32.dll SHFormatDrive",<br />
				"Shell32.dll Control_RunDLLA inetcpl.cpl 0",<br />
				"Shell32.dll Control_RunDLLA appwiz.cpl",<br />
				"Shell32.dll Control_RunDLLA timedate.cpl",<br />
				"Shell32.dll Control_RunDLLA desk.cpl",<br />
				"Shell32.dll Control_RunDLLA modem.cpl",<br />
				"Shell32.dll Control_RunDLLA mmsys.cpl 0",<br />
				"Shell32.dll Control_RunDLLA main.cpl @0",<br />
				"Shell32.dll Control_RunDLLA netcpl.cpl",<br />
				"Shell32.dll Control_RunDLLA password.cpl",<br />
				"Shell32.dll Control_RunDLLA sysdm.cpl 0",<br />
				"Shell32.dll Control_RunDLLA intl.cpl 0",<br />
				"Shell32.dll Control_RunDLLA mmsys.cpl @1",<br />
				"Shell32.dll Control_RunDLLA joy.cpl",<br />
				"Shell32.dll Control_RunDLLA main.cpl @1",<br />
				"DevMgr.dll DeviceManager_ExecuteA"<br />
			};<br />
			<br />
			int i = (int) Dialog - 1;<br />
			Process p = new Process();<br />
			p.StartInfo.FileName = "Rundll32.exe";<br />
			p.StartInfo.Arguments = Args[i];<br />
			//p.StartInfo.UseShellExecute = false;<br />
			//p.StartInfo.ErrorDialog = true;<br />
			//p.StartInfo.RedirectStandardError = true;<br />
			p.Start();<br />
			//p.WaitForExit();<br />
			//string output = p.StandardError.ReadToEnd();<br />
		}<br />
	}<br />
}

In settings form of my application i call this method:

using System;<br />
-----------<br />
----------<br />
SystemDialogs.ShowDialog(SystemDialogs.Dialogs.SD_INTERNET_OPTIONS);

...for showing the internet options dialog as no modal Frown | :(

...

suggestions ?

tnx to all and excuse me for eventual grammar's errors .... i'm italian Wink | ;)

Dan Neely14-Nov-05 3:52

Dan Neely

14-Nov-05 3:52

Is there a function that will automatically turn a relative path into an abosolute one? I could use Application.ExecutablePath and iterate up a level for each ..\ in the relative one if not but I'd just as soon not reinvent the wheel.

Re: Converting a relative path into an absolute one

Curtis Schlak.14-Nov-05 4:55

Re: Converting a relative path into an absolute one

14-Nov-05 4:55

Have you looked at the Path.GetFullPath( string ) method?

From the documentataion:

Returns the absolute path for the specified path string.

For example, if I write a console application that contains the following statement as the sole entry in the Main function:

Console.WriteLine( System.IO.Path.GetFullPath( "..\\.\\moo.txt" ) );

and run it from the Command window, I'd get:

c:\dir1\dir2\dir3\dir4> RunGetFullPathTest.exe

c:\dir1\dir2\moo.txt

c:\dir1\dir2\dir3\dir4>

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

Dan Neely14-Nov-05 5:19

Dan Neely

14-Nov-05 5:19

Curtis S. wrote:
Have you looked at the Path.GetFullPath( string ) method?

Thank you, that's exactly what I was looking for.

Re: Converting a relative path into an absolute one

Curtis Schlak.14-Nov-05 5:30