Cannot use property .Text...
... but you can create a dynamic bitmap to replace the text, allowing you to format it, but you want:

Button button = new Button();
button.Name = "btn" + idDanych;
button.Width = 100;
button.Height = 100;
button.Location = new Point(0, 0);
button.Text = "";
Bitmap bmp = new Bitmap(button.ClientRectangle.Width, button.ClientRectangle.Height);
using (Graphics G = Graphics.FromImage(bmp))
{
G.Clear(button.BackColor);
string line1 = "( " + Wieszak + " ) " + Haczyk;
string line2 = KodEAN;
StringFormat SF = new StringFormat();
SF.Alignment = StringAlignment.Center;
SF.LineAlignment = StringAlignment.Near;
using (Font arial = new Font("Arial", 12))
{
Rectangle RC = button.ClientRectangle;
RC.Inflate(-5, -5);
G.DrawString(line1, arial, Brushes.Black, RC, SF);
}
using (Font courier = new Font("MS Courier", 24))
{
SF.LineAlignment = StringAlignment.Center;
G.DrawString(line2, courier, Brushes.Red, button1.ClientRectangle, SF);
}
}
button.Image = bmp;
button.ImageAlign = ContentAlignment.MiddleCenter;
this.Controls.Add(button);
You will need to find the best combination of font sizes, StringFormat layouts and / or positioning to make them look as desired. There are other DrawString () overloads for rendering text in different ways.
, , . . border, .