private void ButtonAddEnemyClick(object sender, EventArgs e)
{
var index = this.listBoxEnemies.SelectedIndex;
if (index >= 0)
{
var sprite = new EnemySprite(Project.Data.Enemies[index + 1]);
this.xnaPanel.AddSprite(sprite);
}
if (this.xnaPanel.Sprites.Count >= 12)
this.buttonAddEnemy.Enabled = false;
}