C# Windows Formun, boyutunu süzülerek büyültme

        private void Button1_Click(object sender, EventArgs e)


       
{

            tmrAra.Enabled = true; // timer'i başlatıyoruz.

        }

        private void tmrAra_Tick(object sender, EventArgs e) // timer

        {

            if ( grpara.Visible == false)

            {

                 for (int i = 0; i < 10; i++)

            {

                Thread.Sleep(10);

            this.Height = this.Height + 10;

            this.Refresh();

 

            toolara.Text = "Müşteri Bul (Kapat)";

            if (this.Height==500)

            {

                  tmrAra.Enabled = false;

                  grpara.Visible = true;

            }

            }

            }

            else

            {

                for (int i = 0; i < 10; i++)

                {grpara.Visible = false;

                    Thread.Sleep(10);

                    this.Height = this.Height - 10;

                    this.Refresh();

                    toolara.Text = "Müşteri Bul (Aç)";

                    if (this.Height == 470)

                    {

                        tmrAra.Enabled = false;                       

                    }

                }

            }          

        }