Untitled

Creating Windows Form controls during execution
TextBox textBox = new TextBox();
textBox.Location = Some Point on your form or container.
this.Controls.Add(textBox);

int topValue = 0;
for (int i = 0; i < numericUpDown1.Value; i++) {
  TextBox textbox = new TextBox();
  textBox.Location = new Point(0, topValue);
  this.Controls.Add(textBox);

  topValue += textBox.Height + 2;
}

numericUpDown1.Maximum = int.Parse(textBox1.Text);