A form that cannot be closed

Question

Hi all,

I am making an application that I really don't want the user to be able to close the application be clicking the red 'X' on the upper right hand side of the window. Instead I want them to be able to only exit from a drop down menu (ie File --> Close). Can anyone please tell me how to accomplish this? Thanks.

Answer 1

Subscribe to the FormClosing event of the form and cancel if it it was trigger by clicking on 'X'. You can also remove X by using ControlBox property

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MCTS, CodeProject MVP 2008

Answer 2

Add bool variable on Form level like:

bool _CanExit;

On menuExit click event you will set this variable to true;

In FormClosing event handler, you will check this variable and if is not click you will cancel form closing:

if (!_CanExit)
{
     e.Cancel = true;
}

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MCDBA, MCSD, MCITP http://sharpsource.blogspot.com/

Answer 3

Try this: This disables the X and disables it when they try to right click on the form to close.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsApplication1
{
    public partial class Form1 : Form
   {
        [DllImport("user32.dll")]
        static extern bool EnableMenuItem(IntPtr hMenu, uint uIDEnableItem, uint uEnable);
        [DllImport("user32.dll")]
        static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);
        internal const UInt32 SC_CLOSE = 0xF060;
        internal const UInt32 MF_ENABLED = 0x00000000;
        internal const UInt32 MF_GRAYED = 0x00000001;
        internal const UInt32 MF_DISABLED = 0x00000002;
        internal const uint MF_BYCOMMAND = 0x00000000;

        public Form1()
        {
             InitializeComponent();
             EnableCloseButton(this, false);
        }

       private void button1_Click(object sender, EventArgs e)
       {
           Application.Exit();
       }

      public static void EnableCloseButton(IWin32Window window, bool bEnabled)
      {
          IntPtr hSystemMenu = GetSystemMenu(window.Handle, false);
          EnableMenuItem(hSystemMenu, SC_CLOSE, (uint)(MF_ENABLED | (bEnabled ? MF_ENABLED : MF_GRAYED)));
      }

}

}

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 4

John,

Thank you very much. The only trouble that I am running into is:

public Form1()
        {
             InitializeComponent();
             EnableCloseButton(this, false);  // <-- this part
        }

I know it is very basic, but should EnableCloseButton be an actual button on my form? Um..I probably will figure it out soon enough. Thanks, and any other suggestions are welcome.

Answer 5

One more thing....The error says, "EnableCloseButton does not exist in the current context"

Even when I put another item such as button1 in the place of EnableCloseButton it gives me the same error.

Answer 6

GGCO said:

One more thing....The error says, "EnableCloseButton does not exist in the current context"

Even when I put another item such as button1 in the place of EnableCloseButton it gives me the same error.

EnableCloseButton is a static function in John's code snippet above. Looks like you did not put that in yet.

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http://blog.voidnish.com

Answer 7

John or anyone else, do you know how to disable the close button on the Console?

Thanks.

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AlexB

Answer 8

 This is how I block my forms from being closed by that button:

private void pushSTOP_Click ( object sender, EventArgs e )

{

this.unBlockAction = false;

this.Close ( );

}                                              // pushSTOP_Click

override protected void OnClosing ( CancelEventArgs ee )

{

if ( this.unBlockAction == false )

{

ee.Cancel = false;

}

else

{

ee.Cancel = true;

}

}                                              //  OnClosing

this.unBlockAction  is a boolean variable at the class level.

pushSTOP is the button that closes the form.

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AlexB

Answer 9

It is called that because X is a button (Call it whatever you want, it calls the Win32API). Note this will also disable the close when you right click on the top of your form, so make sure you have a close button that calls Application.Exit()

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 10

Alex, I can certainly find out how to do that with the Console. You can also change the Console title bar as well with the Win32 API

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 11

Go to this site and get the .NET add in for free, you will learn tons about Win32

http://www.pinvoke.net/

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 12

I know how to change the Console title. I have this code and use it all the time. I need to block it from being closed manually by oversight since I frequently press buttons before I think.

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AlexB

Answer 13

I am aware of that site, John. It takes time to investigate. Also I went thu it all at least twice. I could not find any methods or constants related to it.

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AlexB

Answer 14

JohnGrove and Nishant Sivakumar,

Thank you both! My problem is solved. Thanks alot!

Answer 15

Here is how you do it to a Console window:

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace ConsoleApplication1
{
    class Program
    {
          [DllImport("user32.dll")]
          static extern bool EnableMenuItem(IntPtr hMenu, uint uIDEnableItem, uint uEnable);
          [DllImport("user32.dll")]
          static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);
          internal const UInt32 SC_CLOSE = 0xF060;
          internal const UInt32 MF_ENABLED = 0x00000000;
          internal const UInt32 MF_GRAYED = 0x00000001;
          internal const UInt32 MF_DISABLED = 0x00000002;
          internal const uint MF_BYCOMMAND = 0x00000000;
          [DllImport("kernel32.dll")]
          static extern IntPtr GetConsoleWindow();

          static void Main(string[] args)
         {
               EnableCloseButton(GetConsoleWindow(), false);
               Console.WriteLine("Press x to close");
               if (Console.ReadLine() == "x")
               {
                    return;
               }
         }

         public static void EnableCloseButton(IntPtr window, bool bEnabled)
         {
              IntPtr hSystemMenu = GetSystemMenu(GetConsoleWindow(), false);
              EnableMenuItem(hSystemMenu, SC_CLOSE, (uint)(MF_ENABLED | (bEnabled ? MF_ENABLED : MF_GRAYED)));
         }
    }

}

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 16

Can we close this thread now?

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Answer 17

JohnGrove said:

Can we close this thread now?

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John Grove - TFD Group, Senior Software Engineer, EI Division, http://www.tfdg.com

Oh, John, you are a genius. If it is what I have in mind that's great. Thank you.

Yep, It appears exactly what I wanted for so long. I posted this request in the past two times and never got an answer.

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AlexB