获取属性名：PropertyNameHelper

获取属性名：PropertyNameHelper

namespace NCS.Infrastructure.Querying

{

    public static class PropertyNameHelper

    {

        public static string ResolvePropertyName<T>(Expression<Func<T, object>> expression)

        {

            var expr = expression.Body as MemberExpression;

            if (expr == null)

            {

                var u = expression.Body as UnaryExpression;

                expr = u.Operand as MemberExpression;

            }

            return expr.ToString().Substring(expr.ToString().IndexOf(".") + );

        }

        public static string ResolvePropertyName<T>(Expression<Func<T>> expression)

        {

            var expr = expression.Body as MemberExpression;

            if (expr == null)

            {

                var u = expression.Body as UnaryExpression;

                expr = u.Operand as MemberExpression;

            }

            return expr.ToString().Substring(expr.ToString().IndexOf(".") + );

        }

    }

}

使用：

        /// <summary>

        /// 创建Criterion对象,示例1:

        /// Criterion.Create<Product>(p=>p.Color.Id, id, CriteriaOperator.Equal);

        ///

        /// 示例2：类对象中的另一个类对象的属性创建Criterion，

        /// 例如DataPoint的一个属性ModuleBelongTo的类型是Module，而Module有int类型的Id属性，

        /// 即类的结构如下：

        /// DataPoint datapoint = new DataPoint();

        /// datapoint.ModuleBelongTo = new Module();

        ///

        /// 用datapoint.ModuleBelongTo.Id创建Criterion

        /// Criterion.Create<DataPoint>(p => p.ModuleBelongTo.Id, 2, CriteriaOperator.Equal)

        /// </summary>

        /// <typeparam name="T"></typeparam>

        /// <param name="expression"></param>

        /// <param name="value"></param>

        /// <param name="criteriaOperator"></param>

        /// <returns></returns>

        public static Criterion Create<T>(Expression<Func<T, object>> expression, object value, CriteriaOperator criteriaOperator)

        {

            string propertyName = PropertyNameHelper.ResolvePropertyName<T>(expression);

            Criterion criterion = new Criterion(propertyName, value, criteriaOperator);

            return criterion;

        }

                query.AddCriterion(Criterion.Create<DataPointHistoryData>(p => p.DataPoint.Id, request.DataPointId, CriteriaOperator.Equal));