C#

void btnRun_click(object sender, EventArgs e)
{
  if (btnRun.Tag != null)
    MessageBox.Show("Not now you idiot, I'm busy.");
  else 
    ThreadPool.QueueUserWorkItem(new WaitCallback(process));
}


void process(object state)
{
  running = true;
  // Use try-finally so the flag is updated even if an exception occurs.
  try
  {
     ...
  }
  finally
  {
     running = false;
  }
}

public Settings setting = new Settings();

settings = new Settings();
settings.ShowDialog();
...

samskiter wrote:

I have declared my form as a class member variable ... because i want to only be able to show it once

try
            {
                this.setting.Activate();
            }
            catch
            {
                this.setting = new Settings();
                this.setting.Show();
            }