.NET (Core and Framework)

public void set_BorderStyle(BorderStyle value) {
  if (!(Enum.IsDefined(typeof(BorderStyle), value)))
    throw new InvalidEnumArgumentException("value", value, typeof(BorderStyle));
  if (this.borderStyle != value) {
    this.borderStyle = value;
    this.RecreateHandle(); // window is destroyed, and recreated using the CreateParams property
  }
}


protected virtual CreateParams get_CreateParams() {
  CreateParams local0;
  BorderStyle local1;

  local0 = this.CreateParams;
  local1 = this.borderStyle;
  switch (local1 - 1) {
    case 1:
      local0.ExStyle = local0.ExStyle | 512;
      break;
    case 0:
      local0.Style = local0.Style | 8388608;
      break;
  }
  return local0;
}