if (this.InvokeRequired)
{
    BeginInvoke(new MyDelegate(delegate()
    {
        timer.Enabled = true;
    }));
}

public bool TimerEnable
    {
        set
        {
            this.Invoke((MethodInvoker)delegate
            {
                this.timer.Enabled = value;
            });
        }
    }


    public static void timerEnable()
    {
        var form = Form.ActiveForm as Form1;
        if (form != null)
            form.TimerEnable = true;
    }

public static class ControlExtensions
{
  public static TResult InvokeEx<TControl, TResult>(this TControl control,
                            Func<TControl, TResult> func)
    where TControl : Control
  {
    if (control.InvokeRequired)
    {
      return (TResult)control.Invoke(func, control);
    }
    else
    {
      return func(control);
    }
  }
}

new Thread(() =>
  {
    Thread.Sleep(1000);
    this.InvokeEx(f => f.timer1.Enabled = true);
  }).Start();