获取属性名：PropertyNameHelper

最新推荐文章于 2021-08-15 19:20:16 发布

转载最新推荐文章于 2021-08-15 19:20:16 发布 · 177 阅读

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原文链接：http://www.cnblogs.com/easy5weikai/p/3230134.html

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(".") + 1);
        }

        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(".") + 1);
        }
    }
}

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));

转载于:https://www.cnblogs.com/easy5weikai/p/3230134.html