Trying to close control parent form using SendMessage while not working in my app it will close other apps

Question

4.00/5 (1 vote)

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.NET3.5

Hi All,

I am trying to get the parent form to close and its not working. If I send the exact same thing to say Notepad it works fine and closes the window but not in my solution. Here is my code:

C#

protected override void OnMouseClick(MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        if (aaaRectClose.Contains(e.Location) && this.Parent != null)
        {            
            IntPtr frmHandle = (this.Parent is Form) ? this.Parent.Handle : 0;
            if(frmHandle > 0)
            {
                SendMessage(frmHandle, ((uint)0x0112), ((int)0xF060), 0);  
            }          
        }
    }
}

[DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, int lParam);

Any ideas why this works for other applications but not my own? Any help or suggestions would be greatly appreciated!

Thank you!

Posted 23-Jun-11 14:09pm

PhillipFromAZ

Updated 23-Jun-11 19:29pm

Ramalinga Koushik

v2

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4 solutions

Solution 3

Look easy way

C#

public partial class Form2 : Form
    {
        private Form _ParentForm;           

        public Form2(Form form)
        {
            InitializeComponent();
            this._ParentForm = form;            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this._ParentForm.Close();
        }
    }

Now to use do this

C#

Form2 form = new Form2(this);
            form.Show();

Posted 23-Jun-11 17:20pm

charles henington

Comments

Christian Graus 23-Jun-11 23:25pm

Ideally, you should just use the Parent property to find the form in question, or use a delegate to tell it to close, not keep references to forms like this.

charles henington 23-Jun-11 23:38pm

true but actually the correct way is to use ownedForm and owner like this

Form2 newForm = new Form2();
this.AddOwnedForm(newForm);
newForm.Show();

then on the exit call use

this.Owner.Close();

Check out the example Windows-Form-application by SAKryukov

Solution 1

This makes no sense at all. Your parent form won't close while a child is open, and as you have the parent form, it's inside your app, why not just tell it to close, or tell the Application to close, instead of using SendMessage ? You should write obsfucated code like this only when you have to.

Posted 23-Jun-11 14:11pm

Christian Graus

Comments

PhillipFromAZ 23-Jun-11 20:16pm

Ok, this is a nested control inside of a form. Its a sort of generic control panel that is used in most of our forms. The portion in question is the close button (the button isn't a button per-si but a rectangle area). I recently got a suggestion from a co-worker to use sendmessage for compatibility issues. I originally had this.Parent.Close() and worked great.

TRK3 23-Jun-11 20:46pm

There isn't any compatibility issue with this.Parent.Close() -- that would be the standard way to tell your parent to close...

charles henington 23-Jun-11 23:00pm

What do You Mean "This makes no sense at all. Your parent form won't close while a child is open" Of Course it will you need to reevaluate that statement!!!

Christian Graus 23-Jun-11 23:24pm

If your parent form is the main form, and it's really marked as the parent/owner, I don't believe it will close, when it's got a child form open.

PhillipFromAZ 23-Jun-11 23:03pm

TRK3, thank you for your comment it appears as though I will need to go back to that as it seems as though I have stumped more than just myself. I just really hate to admit defeat.

charles henington 23-Jun-11 23:25pm

Reason for my vote of 1... see earlier comment plus my solution above

Christian Graus 24-Jun-11 0:45am

Unfortunately, you are 100% wrong. If you close the main form of an application, the application closes. If you create a form that is NOT the main window, and then have a child form show, and call Close on it's parent, it does not work. A parent will not close if it has a child window open. So, I suggest in future before you 1 vote people, you do some basic research and check your premise, because in this case, you've made an idiot of yourself.

PhillipFromAZ 24-Jun-11 1:18am

All of this is irrelevant as I'm not doing parent form/child form, i'm doing parent form/child control

Christian Graus 24-Jun-11 2:55am

OK, in that case, it's all odd. Why would you do all this to close a form from a control on the form ? Why not just get the form from the control without sending messages ?

charles henington 24-Jun-11 17:18pm

I agree 100% Christian check out my reply on their solution

PhillipFromAZ 24-Jun-11 3:08am

All I can say is read my description in my solution above. I'm not sure how to explain it any better than I have there. I do apologize if I haven't found a way to describe properly my intent/problem/solution but I do appreciate you taking time from your day to offer solutions to my problem it is greatly appreciated!

Solution 2

<big>Application.Exit();</big>

Posted 23-Jun-11 16:49pm

charles henington

Comments

PhillipFromAZ 23-Jun-11 23:01pm

Charles, Application.Exit() is not the answer as its not intended to exit the application. Intention is just to close the parent form and continue processing in the normal way as if the user pressed the "X" button in the upper right hand of the window.
I just don't understand why it will close any other window I tell it, just not its parent window and yes it is a control and not a child form.
Any help?

[no name] 24-Jun-11 1:29am

It won't help so i gave you 1 vote.

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PhillipFromAZ · Accepted Answer · 2011-06-23T18:14:00

Ok, after hours of checking MSDN and poking around System.Windows.Forms.Form using Telerik I finally have a working solution and here's what I got:

C#

if (aaaRectClose.Contains(e.Location) && aaaParentForm != null)
{
    if (aaaRectClose.Contains(e.Location) && this.Parent != null)
    {
        IntPtr frmHandle = (this.Parent is Form) ? this.Parent.Handle : IntPtr.Zero;
        if (frmHandle != IntPtr.Zero)
        {
            SendMessage(frmHandle, 16, 0, 0);
        }
    }
}

Basically here is what I was trying to accomplish: A custom control could be included in any form in the project. This control contained several "Virtual" buttons which where part of an image. aaaRectClose was a Rectangle that contained the bounds for the "Close" button. When pressed it needed to close the form as if pressing the "X" in the upper right corner of standard Windows forms. The reason for including this close button is some of the forms may be borderless.

Anyways thank you to everyone who read my question and proposed a solution your efforts have been appreciated.

The above code does work for anyone who may eventually have the same silly requirements thrown in their lap with someone higher than yourself demanding things that make no since to you. Otherwise simply issue the "this.Parent.Close()" statement as its much simpler.

Whilst I couldn't find or there is no documentation on "SendMessage(IntPtr, 16, 0, 0)" nor does it coincide with what is on MSDN it does work.

-Phil