如何有效地保留.Net字体对象？

public static String GetFontString(string fontFamily) {
    Font font = new Font(fontFamily, 18);
    Dictionary<int, Font> fontDictionary = font.Dictionary.MakeSet();
    StringBuilder fontStringBuilder = new StringBuilder();

    foreach (KeyValuePair<int, Font> keyValuePair in fontDictionary) {
        string fontString = keyValuePair.Value.ToString();
        fontStringBuilder.Append(fontString);
    }

    return fontStringBuilder.ToString();
}

private static void Main(string[] args) {
    Dictionary<int, Font> fontDictionary = font.Dictionary.MakeSet(); // 创建使用唯一字体对象的集合
    string fontString = GetFontString("Microsoft YaHei"); // 获取包含所有字体对象的字符串

    fontDictionary.Remove(); // 删除不再使用的字体对象
}