貞愛講

 private void Form1_Load(object sender, EventArgs e)
 {
     ((Bitmap)this.BackgroundImage).MakeTransparent();
 }

 private void Form1_DoubleClick(object sender, EventArgs e)
 {
      this.Close();
 }

bool start = false;
int x, y;
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
     start = true;
     this.x = e.X;
     this.y = e.Y;
}

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
     if (start)
     {
         this.Location = new Point(this.Location.X + e.X - x, this.Location.Y + e.Y - y);
      }
}

private void Form1_MouseUp(object sender, MouseEventArgs e)
{
     start = false;
}

        private void button1_Click(object sender, EventArgs e)
        {
            foreach (Control c in Controls)
            {
                if (c is TextBox)
                    c.Text = "";
            }