Mono.Debugger.GUIManager.StepInto C# (CSharp) Method

        public void StepInto(Thread thread)
        {
            thread.Step (ThreadingModel, StepMode.SourceLine);
        }

 public void StepLine()
 {
     if (running)
     {
         throw new InvalidOperationException("Target already running");
     }
     OnStartRunning();
     guiManager.StepInto(activeThread);
 }