title: Application.Exit() and FormClosing event in Vb.net
body: <p>I have a single windows form application that is running in system tray icon.If the user press X button of the windows form a messagebox is displayed with Yes and No ( Yes ->close the form---No->keep the form running in system tray icon).
  I was thinking to prevent the scenario when the user open another instance of the application when there is already an instance running so i have used this code :</p>
  
  <pre><code> If Process.GetProcessesByName(Process.GetCurrentProcess.ProcessName).Length&gt; 1 Then 
   MessageBox.Show("Another instance is running", "Error Window", MessageBoxButtons.OK,
      MessageBoxIcon.Exclamation)
      Application.Exit()
  End If
  </code></pre>
  
  <p>The problem is that when i want to test this the message is displayed but after i press ok, a new messagebox appears (that one from Private Sub Form_FormClosing ).If i choose NO i will have to instance running!
  I have read that Application.Exit fires the Form_FormClosing event.</p>
  
  <p>Is there any possibility to cancel the triggering of the Form_FormClosing event,or am i doing something wrong?</p>
  
  <p>'this is the formclosing procedure </p>
  
  <pre><code>Private Sub Form_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
      Try
          Dim response As MsgBoxResult
          response = MsgBox("Are you sure you want to exit", CType(MsgBoxStyle.Question + MsgBoxStyle.YesNo, MsgBoxStyle), "Confirm")
  
          'If the user press Yes the application wil close
          'because the application remains in taskmanager after closing i decide to kill the current process
          If response = MsgBoxResult.Yes Then
              Process.GetCurrentProcess().Kill()
          ElseIf response = MsgBoxResult.No Then
              e.Cancel = True
              Me.WindowState = FormWindowState.Minimized
              Me.Hide()
              NotifyIcon1.Visible = True
          End If
  </code></pre>
  
  <p>PS: I am not a programmer so please don't be to harsh with me:)</p>