Question

When exiting the program if the programmer handles the FormClosing event if there is unsaved data the programmer can prompt a save dialog asking them if they want to save, not save, or cancel the operation.

In the FormClosing event if they hit Cancel, to cancel the operation you set e.Cancel = true;. This is fine. However, in the menu if the user hits the Exit button then the same thing should occur except instead of doing e.Cancel = true; it should just do return; because it’s handle menu item Click event instead of a FormClosing event.

Right now I pretty much have the code duplicated and was wondering if there was a way to handle this to avoid the duplication in an elegant and understandable fashion.

private void FrmEditorFormClosing(object sender, FormClosingEventArgs e)
{
    if (NeedsToSave)
    {
        DialogResult saveChangesDialog = 
MessageBox.Show("There are unsaved changes. Save now?", 
"Xml Editor", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question);

        if (saveChangesDialog == DialogResult.Yes)
        {
            Save();
        }
        else if (saveChangesDialog == DialogResult.Cancel)
        {
            e.Cancel = true; // Only difference
        }
    }
}

private void ExitToolStripMenuItemClick(object sender, EventArgs e)
{
    if (NeedsToSave)
    {
        DialogResult saveChangesDialog = 
MessageBox.Show("There are unsaved changes. Save now?", 
"Xml Editor", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question);

        if (saveChangesDialog == DialogResult.Yes)
        {
            Save();
        }
        else if (saveChangesDialog == DialogResult.Cancel)
        {
            return; // Only difference
        }
    }

    Close();
}

Answer 1

You shouldn’t need to do this. Calling Close in your menu click handler should cause the FormClosing event to fire and you can cancel it there.