RoundButton Kullanımı

Form1.cs

 private void Form1_Load(object sender, EventArgs e)
        {
            RoundButton rb = new RoundButton();
            rb.Text = "round btn";
            rb.BackColor = Color.Red;
            this.Controls.Add(rb);                
        }

RoundButton.cs

   class RoundButton:Button
    {
        protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
        {
            GraphicsPath grPath = new GraphicsPath();
            grPath.AddEllipse(0, 0, ClientSize.Width, ClientSize.Height);
            this.Region = new System.Drawing.Region(grPath);
            base.OnPaint(e);
        }
    }