Windows Mobile中如何使PicturesBox控件上的Label控件背景透明

void pictureBox1_Paint(object sender, PaintEventArgs e)

         {

             foreach (Control C in this.Controls)

             {

                 if (C is Label)

                 {

                     Label L = (Label)C;

                     L.Visible = false;

                     e.Graphics.DrawString(L.Text, L.Font, new

           SolidBrush(L.ForeColor), L.Left - this.pictureBox1.Left, L.Top - this.pictureBox1.Top);

                 }

             }

 

        }