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How to handle form closing events

I am using Windows Forms in c# and have problems with how and when the the different forms (i have 2) should close and not. It is very annoying since i feel that i should be able to fix it. But here we go.
I have two forms, one MainForm that calls another form called ContactForm.
The MainForm:
private void btnAdd_Click(object sender, EventArgs e)
{
ContactForm frmContact = new ContactForm();
int index = lstCustomers.SelectedIndex;
//If a customer is selected, export data for the selected customer to ContactForm
if (index != -1)
{
frmContact.ContactData = customerMngr.GetCustomer(index).ContactData;
}
if (frmContact.ShowDialog() == DialogResult.OK) //Show the ContactForm object
{
//The user has chosen the OK button - add the new customer object
customerMngr.AddCustomer(frmContact.ContactData); //??
UpdateCustomerList();
}
if (frmContact.ShowDialog() == DialogResult.Cancel)
{
return;
}
}
And the form that is called:
OK button.
private void btnOK_Click(object sender, EventArgs e)
{
if (ValidateInput())
{
this.DialogResult = DialogResult.OK;
this.Close();
}
}
Cancel button:
private void btnCancel_Click(object sender, EventArgs e)
{
if (MessageBox.Show("Do you want to cancel and discard all data?", "Cancel input", MessageBoxButtons.YesNo,
MessageBoxIcon.Question, MessageBoxDefaultButton.Button2) == DialogResult.Yes)
{
this.DialogResult = DialogResult.Cancel;
this.Close();
}
}
When the OK button in the ContactForm is used i want it to close, which works. When i press the cancel button, and no (in the box that appears), i want the form to stay open with the input still intact. Right now it doesn´t work.
Any ideas?
/Martin

Your code is alright. I think the problem lies in your Cancel Button itself. By this I mean that you probably attached (by designer or somewhere in code) DialogResul.Cancel to your button btnCancel.DialogResul property. To fix this simply set it to DialogResult.None.
If I'm right this is what is closing your second form.
See MSDN for more information.

How do i close shut down my application from another Form?

I have this event in a new Form:
private void CrawlLocaly_FormClosed(object sender, FormClosedEventArgs e)
{
}
Im not sure if to use Closed or Closing.
The reason is that i want to check if the user shut down the program for example by just closing the application from the taskbar.
If he did close it from the taskbar mouse right click then close then i want it to close all the program and not only this Form.
How can i do it ?

Application.Exit();
Will shut down your application.
Im not really sure if you can detect if he closed it via rightmouse menu. As far as I know you can only see the reasons provided in the FormClosedEventArgs. FormClosing will provide you with same reasons.

Use this event:
private void Form_FormClosing(object sender, FormClosingEventArgs e)
{
if(e.CloseReason == CloseReason.UserClosing)
{
//close forms
Application.Exit();
}
}
There is no way to check whether user closed your form by clicking 'X' or through TaskBar or any other way as the result of CloseReason will always be CloseReason.UserClosing

Well I Stick with such issue also.
In mine app I have 2 forms, #1 main, #2 - for settings - if user close it i want to know save settings or not. Also if settings are null - close app not only form, if user click button save - I want to close (hide) #2 form.
So where is my solution we set tag value to 1 if click button save, so we will know "who" try to close form:
Predefined:
btnSave.Tag = 0;
On save button click event:
btnSave.Tag = 1;
this.Hide();
its will trigger onclose event:
private void frmLogin_FormClosing(object sender, FormClosingEventArgs e)
{
if (btnSave.Tag.ToString() == "0")
{
DialogResult dlg = MessageBox.Show("Do you want to exit without finished setup connection?", "Form", MessageBoxButtons.YesNo, MessageBoxIcon.Information);
if (dlg == DialogResult.No)
{
e.Cancel = true;
}
else
{
e.Cancel = false;
this.Dispose();
Application.Exit();
}
}
else
{
this.Hide();
}
}

How to close entire application when application has more than 2 forms without showing messagebox more than once

I am developing a application using windows forms. The project contains 3 forms: one login form which is the main form and two others which are child forms to the login form.
My problem is when want to close the total application by using Application.Exit() in form closing event my messagebox showing the dialog more than once.
1.This code in Login form i.e main form:
private void FrmLogIn_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult loginResult = MessageBox.Show("Do you want to close this application?","Close",MessageBoxButtons.YesNo,MessageBoxIcon.Warning);
if (loginResult == DialogResult.Yes)
{
Application.Exit();
}
}
2.AdminForm closing event which is child form to login form:
private void FrmAdmin_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult loginResult = MessageBox.Show("Do you want to close this application?","Close",MessageBoxButtons.YesNo,MessageBoxIcon.Warning);
if (loginResult == DialogResult.Yes)
{
Application.Exit();
}
}
3.Billoperations form closing event which is child form to login form:
private void FrmBillOperation_FormClosing(object sender, FormClosingEventArgs e)
{
DialogResult loginResult = MessageBox.Show("Do you want to close this application?","Close",MessageBoxButtons.YesNo,MessageBoxIcon.Warning);
if (loginResult == DialogResult.Yes)
{
Application.Exit();
}
}
When i click the close button in any form it will show MessageBox message only once. Please help me.

Make all FormClosing methods call a ApplicationShutdown function which handles this in a central place. You don't want to copy this code to every new form you create.
In this method you can check a boolean (watch for thread-safety) called for example IsShuttingDown. If it's already true, leave the method, otherwise you ask the question and start exiting.

The FormClosingEventArgs instance passed to the FormClosing event has a CloseReason property, which will be set to CloseReason.ApplicationExit when the Exit method of the Application class has been invoked: your handlers should check for this condition and if so then take no further action.
private void FrmLogIn_FormClosing(object sender, FormClosingEventArgs e)
{
if (e.CloseReason == CloseReason.ApplicationExit)
return;
...
}

You can try with this code
FormCollection fc = Application.OpenForms;
if (fc!= null && fc.Count > 0)
{
for (int i = 1; i < fc.Count; i++)
{
if (fc!= null && fc.IsDisposed!= true)
{
fc.Dispose();
}
}
}

private void sh_interface_FormClosing(object sender, FormClosingEventArgs e)
{
if (MessageBox.Show("This will close down the whole application. Confirm?", "Close Application", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
foreach (Form f in Application.OpenForms)
{
if (!f.IsDisposed)
f.Dispose();
}
}
else
{
e.Cancel = true;
this.Activate();
}
}
This will close all forms including the hidden forms and the main form from Application.Run(new something())...Also this method works when invoked in inherited classes while coded in template class Form Closing event.

Troubles with onFormClosing in c#

I'm trying to implement some code that asks if the user wants to exit the application I've made.
It's in c# and is a windows form application.
I've had very little sleep this week and can't seem to get my head around the onFormClosing event. Could some please give me the exact code I should use to have code executed when the user clicks on the close button (the 'x' in the top right).
Please find it in your heart to help a sleep deprived moron.

Double-click the form's FormClosed event in the events tab of the Properties window in the designer.
The FormClosing event allows you to prevent the form from closing by setting e.Cancel = true.

Well, the event is called FormClosing and is cancellable. Subscribe to it, do your stuff and let the user close their form. This event is fired if the "x" button is used or if you close the form yourself.
You can subscribe to it in the designer by highlighting the form and looking in the events tab of the properties window, as SLaks says, then double-click it. You don't need to do anything special to cope with the "x" button.

The easiest way is to activate the form in the designer and find the event FormClosing in the properties windows and then just double click the event.
Then just do the following:
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (e.CloseReason == CloseReason.UserClosing)
{
var result = MessageBox.Show("Are you sure you want to exit?", "Exit", MessageBoxButtons.YesNo);
if (result != System.Windows.Forms.DialogResult.Yes)
{
e.Cancel = true;
}
}
}
If you do not specify that the reason has to be UserClosing, it will stop windows from shutting down if you do not exit the program first which is not a good practice.

public Form1()
{
InitializeComponent();
this.FormClosing += new FormClosingEventHandler(Form1_FormClosing);
}
void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (MessageBox.Show("Are you sure that you wan't to close this app", "Question", MessageBoxButtons.OKCancel) == DialogResult.Cancel)
e.Cancel = true;
}
I hope this helps

You can add event handler manually. Example to add event handler in constructor:
public frmMain()
{
InitializeComponent();
FormClosing += frmMain_FormClosing;
}
private void frmMain_FormClosing(object sender, FormClosingEventArgs e)
{
//your code
}

Make derive your form fromf the System.Windows.Forms.Form and put this override:
protected override void OnFormClosing(CancelEventArgs e)
{
if (bWrongClose)
{
bWrongClose = false;
e.Cancel = true; // this blocks the `Form` from closing
}
base.OnFormClosing(e);
}

Visual C#: Exit the Program Check

In Visual C#, how can I detect if the user clicks the X button to close the program? I want to ask the user if they'd like to perform a certain action before exiting. I have an exit button in my program itself, and I know I can code it as follows:
private void exitToolStripMenuItem_Click(object sender, EventArgs e)
{
DialogResult result;
if (logfiletextbox.Text != "")
{
result = MessageBox.Show("Would you like to save the current logfile?", "Save?", MessageBoxButtons.YesNo, MessageBoxIcon.Asterisk);
if (result == DialogResult.Yes)
{
savelog.PerformClick();
}
}
Environment.Exit(0); //exit program
}
But how can I do this for the X button that is already built into the program?

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (MessageBox.Show("cancel?", "a good question", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
e.Cancel = true;
}
}
It's the "FormClosing" - event of the form. Have fun, friend.

Add an event handler for FormClosing on the form.
The Form designer will do this for you automatically if you select the event, but to do it manually:
this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.Main_FormClosing);
And then add the handler into your code:
private void Main_FormClosing(object sender, FormClosingEventArgs e)
{
//Code here
}
If you don't want to close the form then you can set:
e.Cancel = true;

There is a FormClosing event you can bind to that gets fired when the form is about to close. The event handler includes a link to the reason the form is closing (user action, OS shutdown, etc), and offers you an option to cancel it.
Check out the MSDN article here: http://msdn.microsoft.com/en-us/library/system.windows.forms.form.formclosing.aspx

use the Application.Exit or Form.Closing event. Exit won't let you cancel, so Closing is probably a better choice

Just use FormClosing event of form

If you're using a form, you can catch the Form.FormClosing event.
It can be cancelled by setting the Cancel property in the args, based on user input.