public static Expression <Func <T, bool> > Or <T>(
            this Expression <Func <T, bool> > one, Expression <Func <T, bool> > another)
        {
            var candidateExpr     = Expression.Parameter(typeof(T), "candidate");
            var parameterReplacer = new ParameterReplacer(candidateExpr);

            var left  = parameterReplacer.Replace(one.Body);
            var right = parameterReplacer.Replace(another.Body);
            var body  = Expression.Or(left, right);

            return(Expression.Lambda <Func <T, bool> >(body, candidateExpr));
        }
        public static Expression <Func <T, bool> > And <T>(this Expression <Func <T, bool> > one, Expression <Func <T, bool> > other)
        {
            // 首先定义好一个ParameterExpression
            var parameterExp      = Expression.Parameter(typeof(T), "candidate");
            var parameterReplacer = new ParameterReplacer(parameterExp);

            // // 将表达式树的参数统一替换成我们定义好的candidateExpr (表达式分为 参数和body,将参数统一成一个对象)
            var left  = parameterReplacer.Replace(one.Body);
            var right = parameterReplacer.Replace(other.Body);

            var combindBody = Expression.And(left, right);

            return(Expression.Lambda <Func <T, bool> >(combindBody, parameterExp));
        }