C#

private void panel1_MouseDown(object sender, MouseEventArgs e)
        {
            LastX = e.X;
            LastY = e.Y;
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            Graphics G = panel1.CreateGraphics();
            G.DrawLine(Pens.Black, PointX, PointY, LastX, LastY);
            LastX = PointX;
            LastY = PointY;
        }

        private void panel1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                PointX = e.X;
                PointY = e.Y;
                panel1_Paint(this, null);

how will I take ownership in registry subkey... from other owner(TrustedInstaller) to Administrator's. 

I have an array of string which is 

    string[] myarr = new[] { "a", "b", "c" };

Can you please help me how to get this result?

    a
    ab
    abc

I tried this one but I just don't know how to get the value from the array and add it on my list 

    string[] myarray = new string[] { "a", "b", "c" };
                List<string> resultarray = new List<string>();

                int i, j;
                for (i = 0; i <= myarray.Length; i++)
                {
                    for (j = i; j <= i; j++)
                    {

                        


                    }
                }