C#中pictureBox上如何设置label透明

C#中pictureBox上如何设置label透明 
在pictureBox的Paint事件中写下如下代码private 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 - pictureBox1.Left, L.Top - pictureBox1.Top);                }            }        }或者在载入页面的时候在LOAD中写入下面代码：pictureBox1.SendToBack();            label1.BackColor = Color.Transparent;            label1.Parent = pictureBox1;            label1.BringToFront();