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button with an X at the upper-right corner of the form, how to catch this event @ C#

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igalep132

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button with an X at the upper-right corner of the form, how to catch this event @ C#

Sep 12th, 2009

hello,

which event is fired when i close form with X button ? i want event that fired only with X button pressed, i know that there is a FormClosing event, but the problem is that it fires each time when form is closed... also with frm.close()

and i don't want that happen

tanx

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ddanbe

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

You mean you don't want the user to be able to click on it?
A FormClosing event happens before a Form is closed, a FormClosed event happens after a Form is closed. You don't need to implement these if you don't want to.

Last edited by ddanbe; Sep 12th, 2009 at 6:20 pm.

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igalep132

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

no,
what i meant to is that i want to catch some event which is fired when i press X button on the form and only then,
and if i have line like " frm.close()" in my code, the event wont be fired...

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ddanbe

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

You could also set the ControlBox property of the Form to false.

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sknake

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

As far as I know the "X" just sends the form close message to your form and you cannot distinguish the caller. This will work though:

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace daniweb
{
  public partial class frmImage : Form
  {
    private bool allowFormClose = false;
 
    public frmImage()
    {
      InitializeComponent();
    }
 
    protected override void WndProc(ref Message m)
    {
      if (!allowFormClose && (m.Msg == 0x0010)) //form "X"
      {
        System.Diagnostics.Debugger.Break();
        //Do something
      }
      else
        base.WndProc(ref m);
    }
 
    private void button2_Click(object sender, EventArgs e)
    {
      allowFormClose = true;
      this.Close();
    }
  }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace daniweb
{
  public partial class frmImage : Form
  {
    private bool allowFormClose = false;

    public frmImage()
    {
      InitializeComponent();
    }

    protected override void WndProc(ref Message m)
    {
      if (!allowFormClose && (m.Msg == 0x0010)) //form "X"
      {
        System.Diagnostics.Debugger.Break();
        //Do something
      }
      else
        base.WndProc(ref m);
    }

    private void button2_Click(object sender, EventArgs e)
    {
      allowFormClose = true;
      this.Close();
    }
  }
}

[edit]
This is the functionally identical to just canceling the form close in the "FormClosing" event that ddanbe pointed out, with a lot less of a headache.
[/edit]

Last edited by sknake; Sep 12th, 2009 at 7:44 pm.

Scott Knake
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Apex Software, Inc.

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sknake

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

Wait -- You can do it!

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace daniweb
{
  public partial class frmImage : Form
  {
    private bool allowFormClose = false;
 
    public frmImage()
    {
      InitializeComponent();
    }
 
    protected override void WndProc(ref Message m)
    {
      if (!allowFormClose && (m.Msg == 0x0010)) //form "X"
      {
        //System.Diagnostics.Debugger.Break();
        //Do something
      }
      else
        base.WndProc(ref m);
    }
 
    new void Close()
    {
      allowFormClose = true;
      base.Close();
    }
 
    private void button2_Click(object sender, EventArgs e)
    {
      this.Close(); //will work
    }
 
    private void button3_Click(object sender, EventArgs e)
    {
      (this as Form).Close(); //will not work
    }
  }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace daniweb
{
  public partial class frmImage : Form
  {
    private bool allowFormClose = false;

    public frmImage()
    {
      InitializeComponent();
    }

    protected override void WndProc(ref Message m)
    {
      if (!allowFormClose && (m.Msg == 0x0010)) //form "X"
      {
        //System.Diagnostics.Debugger.Break();
        //Do something
      }
      else
        base.WndProc(ref m);
    }

    new void Close()
    {
      allowFormClose = true;
      base.Close();
    }

    private void button2_Click(object sender, EventArgs e)
    {
      this.Close(); //will work
    }

    private void button3_Click(object sender, EventArgs e)
    {
      (this as Form).Close(); //will not work
    }
  }
}

But this method doesn't work very well with inheritance and will probably break things down the road. You're still better off listening to Danny.

Scott Knake
Custom Software Development
Apex Software, Inc.

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Diamonddrake Diamonddrake is offline

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Re: button with an X at the upper-right corner of the form, how to catch this event @

Sep 12th, 2009

That's interesting sknake, I never would have thought of catching the close method like that.

But as far as all these answers go, the Simple response is the X button does only call the form to close. and however you catch that close call, either by wndproc or by a simple form closing event, the trick is to set a flag, just a simple Boolean variable, if its true, cancel the closing and handle your business, if its false, do nothing and allow the form to close.

when you need to call this.Close(); first change your variable. else you can create a public method for your form called DoClose() or something and change the flag there and call close, its up to you.

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