两个小时写了一个加法计算器

第一次进行WPF开发。。。

class Number
    {
        private string str_buffer = null;
        private decimal dec_buffer = 0m;
        public void plus()
        {
            dec_buffer = Convert.ToDecimal(str_buffer);
            this.Result += dec_buffer;
            str_buffer = null;
            dec_buffer = 0m;
            this.expression += "+";
        }
        public void equal()
        {
            dec_buffer = Convert.ToDecimal(str_buffer);
            this.Result += dec_buffer;
            str_buffer = null;
            dec_buffer = 0m;
        }
        private string expression;
        public string Expression
        {
            get { return expression; }
            set
            {
                str_buffer += value;
                expression = this.Expression + value;
            }
        }
        private decimal result;
        public decimal Result
        {
            get { return result; }
            set { result = value; }
        }
        public void clear()
        {
            dec_buffer = 0m;
            str_buffer = null;
            expression = "";
            result = 0m;
        }
    }

binding想用但不会用啊。。