Comments by Tim the Gamer (Top 120 by date)

class MyForm{
  //class level declaration of the stack to hold the draw commands
  private Stack<DrawItem> drawCommands = new Stack<DrawItem>();
  //event handler when the user clicks two points on the picture box to draw a line
  private void DrawingPanelOnMouseClick(object? sender, MouseEventArgs e)
    {
        //increase the indexer if the app is listening
        if (listening)
        {
            indexer += 1;
        }
        //get the point clicked
        var point = new Point(e.X, e.Y);
        pointsClicked.Add(point);
        //add the point to a list
        if (indexer == 2 && drawItem == "Line")
        {
            //push object and points to stack
            drawCommands.Push(new DrawItem("Line",pointsClicked));
            //get the context and draw the line
            drawingPanel.CreateGraphics().DrawLine(drawingPen,pointsClicked[0],pointsClicked[1]);
            //reset the indexer
            indexer = 0;
            //clear the list of points clicked
            pointsClicked.Clear();
            
        }
     //draw as many lines as possible and then try undoing with this method
       private void OnKeyDown(object? sender, KeyEventArgs e)
    {
     if (e.Control && e.KeyCode == Keys.Z)
        {
            //the user is trying to undo the last paint action
            //if the user has performed only one draw command  clear the pane
            if (drawCommands.Count == 1)
            {
                SetPixel(drawingPanel);
            }
            if (drawCommands.Count > 1)
            {
                //push the command at the top of the stack to the redo command list before deleting it
                 redo.Push(drawCommands.Peek());
                //remove the command at the top of the stack
                drawCommands.Pop();
                //loop through the remaining commands and redraw them on the panel
                foreach(var command in drawCommands){
                  //get the command text
                  switch(command.Text){
                    case "Line":
                     drawingPanel.CreateGraphics().DrawLine(drawingPen,command.Points[0],command.Points[1]);
                     break;
                        }
                }
            }
        }
    }
}
//implementation of my drawitem class
public  class DrawItem
{
    private string _itemShape;
    private List<Point> shape = new List<Point>();
    //require the two inside the constructor
    public DrawItem(string itemShape, List<Point> points)
    {
        _itemShape = itemShape;
        shape = points;
    }
    //define the getters and setters for the properties
    public string Item
    {
        get
        {
            return _itemShape;
        }
        
    }

    public List<Point> Points
    {
        get
        {
            return shape;
        }
    }
}