C#

private void pbPreview_MouseMove(object sender, MouseEventArgs e)
{

    if (e.Button == MouseButtons.Left)
    {
        int HW = 20;
        Bitmap b = (Bitmap)pbPreview.Image.Clone();
        Graphics g = Graphics.FromImage(b);
        g.FillEllipse(Brushes.Violet,
        new Rectangle(
            e.X - (HW / 2),
            e.Y - (HW / 2),
        HW,HW));
        pbPreview.Image = (Image)b;
    }
}

private void pbPreview_Paint(object sender, PaintEventArgs e)
{
    int HW = 20;
    Graphics g = e.Graphics;
    g.FillEllipse(Brushes.Yellow,
    new Rectangle(
        this.Cursor.HotSpot.X,
        this.Cursor.HotSpot.Y,
    HW, HW));
}

Christian Graus wrote:

mouse pos is always relative to something...
subtract the top left corner of the picturebox...

Christian Graus wrote:

there are ClientToScreen and ScreenToClient type methods on your controls which you can use.

private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
    int widthHeight = 20;
    using (Graphics g = pictureBox1.CreateGraphics())
    { 
        g.FillEllipse(Brushes.Red, new Rectangle(
            e.X - (widthHeight / 2),
            e.Y - (widthHeight / 2),
            widthHeight,
            widthHeight));
    }
}

public class DrawablePictureBox : PictureBox
{
    private List<Rectangle> rectangles = new List<Rectangle>(100);

    public DrawablePictureBox()
    {
        LineWidth = 20;
        LineColor = Color.Red;
    }

    public int LineWidth
    {
        get;
        set;
    }
    public Color LineColor
    {
        get;
        set;
    }

    protected override void OnMouseMove(MouseEventArgs e)
    {
        base.OnMouseMove(e);
        if (e.Button == MouseButtons.Left)
        {
            Rectangle rectangle = new Rectangle(e.X - (LineWidth / 2),
                e.Y - (LineWidth / 2),
                LineWidth,
                LineWidth);
            rectangles.Add(rectangle);
            Invalidate(rectangle);
        }
    }

    protected override void OnPaint(PaintEventArgs pe)
    {
        base.OnPaint(pe);
        if (rectangles.Count > 0)
            using (Brush brush = new SolidBrush(LineColor))
            {
                foreach (Rectangle rectangle in rectangles)
                    pe.Graphics.FillEllipse(brush, rectangle);
            }
    }
}

jashimu wrote:

I have a application which uses the latest verion excel and it work fine. but when I try to run on any lower version excel it does not work.

I are Troll

cechode wrote:

a lambada expression

among the things i've tried so far 
tried to convert this to a self calling kinda thing
var PP = A.Where(x = > x > 0).SelectMany(g = > B.Where(c = > c > 0).Select(c = > new { aa = g, bb = c })).ToList();

but to no avail

then tried to get a bunch of from clauses ( one for each inner list )

            var ttt = (from g in A
                      from c in B
                      select new { aa = g, bb = c }).ToList();

but also failed 


now i figured i'd ask the experts here 

private IEnumerable<List<int>> Test(List<List<int>> data)
{
     int numDigits = data.Count;
     int lastCount = data[numDigits - 1].Count;
     int[] indices = new int[data.Count];
     while (indices[numDigits - 1] < lastCount)
     {
          //yield return a list composed of data[0][indices[0]], data[1][indices[1]], ...
          
          indices[0]++;
          for (int idx = 0; idx < numDigits - 1; idx++)
          if (indices[idx] == data[idx].Count)
          {
              indices[idx] = 0;
              indices[idx + 1]++;
          }
      }
}