//using System;
//using System.Linq.Expressions;

//namespace IRaCIS.Core.Infrastructure.ExpressionExtend
//{
//    /// <summary>
//    /// 合并表达式 And Or  Not扩展
//    /// </summary>
//    public static class ExpressionExtend
//    {
//        /// <summary>
//        /// 合并表达式 expr1 AND expr2
//        /// </summary>
//        /// <typeparam name="T"></typeparam>
//        /// <param name="expr1"></param>
//        /// <param name="expr2"></param>
//        /// <returns></returns>
//        public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2)
//        {
//            if (expr1 == null) return expr2;
//            else if (expr2 == null) return expr1;

//            //return Expression.Lambda<Func<T, bool>>(Expression.AndAlso(expr1.Body, expr2.Body), expr1.Parameters);
//            ParameterExpression newParameter = Expression.Parameter(typeof(T), "c");
//            NewExpressionVisitor visitor = new NewExpressionVisitor(newParameter);

//            var left = visitor.Replace(expr1.Body);
//            var right = visitor.Replace(expr2.Body);
//            var body = Expression.And(left, right);
//            return Expression.Lambda<Func<T, bool>>(body, newParameter);

//        }
//        /// <summary>
//        /// 合并表达式 expr1 or expr2
//        /// </summary>
//        /// <typeparam name="T"></typeparam>
//        /// <param name="expr1"></param>
//        /// <param name="expr2"></param>
//        /// <returns></returns>
//        public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expr1, Expression<Func<T, bool>> expr2)
//        {
//            if (expr1 == null) return expr2;
//            else if (expr2 == null) return expr1;

//            ParameterExpression newParameter = Expression.Parameter(typeof(T), "c");
//            NewExpressionVisitor visitor = new NewExpressionVisitor(newParameter);

//            var left = visitor.Replace(expr1.Body);
//            var right = visitor.Replace(expr2.Body);
//            var body = Expression.Or(left, right);
//            return Expression.Lambda<Func<T, bool>>(body, newParameter);
//        }
//        public static Expression<Func<T, bool>> Not<T>(this Expression<Func<T, bool>> expr)
//        {
//            if (expr == null) return null;
//            var candidateExpr = expr.Parameters[0];
//            var body = Expression.Not(expr.Body);
//            return Expression.Lambda<Func<T, bool>>(body, candidateExpr);
//        }
//    }
//}