C # Draw and fill the line with the mouse in the window

Namespace WindowsApplication1
{
Public partial class Form1: Form
{
Public Form1 ()
{
InitializeComponent ();
}
Point p1;
Point p2;
ArrayList mya = new ArrayList ();
Private void form=mousedown (object sender, MouseEventArgs e)
{
Point p = new Point (e. X, e. Y );
If (p1.X = 0 & p1.Y = 0)
{
P1 = p;
Mya. Add (p1 );
}
}

Private void form=mouseup (object sender, MouseEventArgs e)
{
Point p = new Point (e. X, e. Y );
P2 = p;
Mya. Add (p2 );
Graphics g = this. CreateGraphics ();
G. DrawLine (Pens. Red, p1, p2 );
P1 = p2;
}

Private void button#click (object sender, EventArgs e)
{
Int number = mya. Count;
Point [] myp = new Point [number];
Object [] ob = new Object [number];

For (int I = 0; I <number; I ++)
{
Ob [I] = mya [I];
Myp [I] = (Point) ob [I];
}
Graphics g = this. CreateGraphics ();
G. DrawPolygon (Pens. Red, myp );
G. FillPolygon (Brushes. Red, myp );
}
}
}