享元模式 文本编辑

GoF 设计模式 享元例子：

示例1：将一段文字的某一段内容转换为大写：

    class TextFormatted
    {
        private  string text;
        private bool[] isFormatted;
        public TextFormatted(string text)
        {
            this.text = text;
            isFormatted = new bool[text.Length];
        }

        public void ToUpper(int start, int end)
        {
            for (int i = start; i < end; i++)
            {
                isFormatted[i] = true;
            }
            var s = text.Select((text,i) => isFormatted[i] ? char.ToUpper(text) : text).ToArray();
            text = string.Join("",s); 
        }
        public string Context => text;
    }
    class Program
    {
        static void Main(string[] args)
        {
            string text = "No matter the ending is perfect or not you cannot disappear from my world";
            TextFormatted textFormatted = new TextFormatted(text);
            textFormatted.ToUpper(3, 9);
            Console.WriteLine(textFormatted.Context);

        }
    }

 

示例2：将一段文字的某一段内容颜色改变：

    class TextFormatted
    {
        private  string text;
        private bool[] isFormatted;
        public TextFormatted(string text)
        {
            this.text = text;
            isFormatted = new bool[text.Length];
        }

        public void ToUpper(int start, int end)
        {
            for (int i = start; i < end; i++)
            {
                isFormatted[i] = true;
            }
            var s = text.Select((text,i) => isFormatted[i] ? char.ToUpper(text) : text).ToArray();
            text = string.Join("",s); 
        }
        public void OutPutAndChangeColor(int start, int end,ConsoleColor color=ConsoleColor.White)
        {
            for (int i = start; i < end; i++)
            {
                isFormatted[i] = true;
            }
            for (int i = 0; i < text.Length; i++)
            {
                if (isFormatted[i]) 
                    Console.ForegroundColor = color;  
                Console.Write(text[i]);
                Console.ForegroundColor = ConsoleColor.White;
            }
        }

        public string Context => text;
    }
    class Program
    {
        static void Main(string[] args)
        {
            string text = "No matter the ending is perfect or not you cannot disappear from my world";
            TextFormatted textFormatted = new TextFormatted(text);
            textFormatted.ToUpper(3, 9);//转换大写
            textFormatted.OutPutAndChangeColor(3, 9,ConsoleColor.Red);//更换颜色

        }
    }