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CloudBuilder/CloudBuilder.Core/Extensions/CollectionExtensions.cs

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+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CloudBuilder.Core.Extensions
+{
+    /// <summary>
+    /// 集合类型字符串排序操作类
+    /// </summary>
+    /// <typeparam name="T">集合项类型</typeparam>
+    public static class CollectionPropertySorter<T>
+    {
+        // ReSharper disable StaticFieldInGenericType
+        private static readonly ConcurrentDictionary<string, LambdaExpression> Cache = new ConcurrentDictionary<string, LambdaExpression>();
+
+        /// <summary>
+        /// 按指定的属性名称对<see cref="IEnumerable{T}"/>序列进行排序
+        /// </summary>
+        /// <param name="source"><see cref="IEnumerable{T}"/>序列</param>
+        /// <param name="propertyName">属性名称</param>
+        /// <param name="sortDirection">排序方向</param>
+        public static IOrderedEnumerable<T> OrderBy(IEnumerable<T> source, string propertyName, ListSortDirection sortDirection)
+        {
+            propertyName.CheckNotNullOrEmpty("propertyName");
+            dynamic expression = GetKeySelector(propertyName);
+            dynamic keySelector = expression.Compile();
+            return sortDirection == ListSortDirection.Ascending
+                ? Enumerable.OrderBy(source, keySelector)
+                : Enumerable.OrderByDescending(source, keySelector);
+        }
+
+        /// <summary>
+        /// 按指定的属性名称对<see cref="IOrderedEnumerable{T}"/>进行继续排序
+        /// </summary>
+        /// <param name="source"><see cref="IOrderedEnumerable{T}"/>序列</param>
+        /// <param name="propertyName">属性名称</param>
+        /// <param name="sortDirection">排序方向</param>
+        public static IOrderedEnumerable<T> ThenBy(IOrderedEnumerable<T> source, string propertyName, ListSortDirection sortDirection)
+        {
+            propertyName.CheckNotNullOrEmpty("propertyName");
+            dynamic expression = GetKeySelector(propertyName);
+            dynamic keySelector = expression.Compile();
+            return sortDirection == ListSortDirection.Ascending
+                ? Enumerable.ThenBy(source, keySelector)
+                : Enumerable.ThenByDescending(source, keySelector);
+        }
+
+        /// <summary>
+        /// 按指定的属性名称对<see cref="IQueryable{T}"/>序列进行排序
+        /// </summary>
+        /// <param name="source">IQueryable{T}序列</param>
+        /// <param name="propertyName">属性名称</param>
+        /// <param name="sortDirection">排序方向</param>
+        /// <returns></returns>
+        public static IOrderedQueryable<T> OrderBy(IQueryable<T> source, string propertyName, ListSortDirection sortDirection)
+        {
+            propertyName.CheckNotNullOrEmpty("propertyName");
+            dynamic keySelector = GetKeySelector(propertyName);
+            return sortDirection == ListSortDirection.Ascending
+                ? Queryable.OrderBy(source, keySelector)
+                : Queryable.OrderByDescending(source, keySelector);
+        }
+
+        /// <summary>
+        /// 按指定的属性名称对<see cref="IOrderedQueryable{T}"/>序列进行排序
+        /// </summary>
+        /// <param name="source">IOrderedQueryable{T}序列</param>
+        /// <param name="propertyName">属性名称</param>
+        /// <param name="sortDirection">排序方向</param>
+        /// <returns></returns>
+        public static IOrderedQueryable<T> ThenBy(IOrderedQueryable<T> source, string propertyName, ListSortDirection sortDirection)
+        {
+            propertyName.CheckNotNullOrEmpty("propertyName");
+            dynamic keySelector = GetKeySelector(propertyName);
+            return sortDirection == ListSortDirection.Ascending
+                ? Queryable.ThenBy(source, keySelector)
+                : Queryable.ThenByDescending(source, keySelector);
+        }
+
+        private static LambdaExpression GetKeySelector(string keyName)
+        {
+            Type type = typeof(T);
+            string key = type.FullName + "." + keyName;
+            if (Cache.ContainsKey(key))
+            {
+                return Cache[key];
+            }
+            ParameterExpression param = Expression.Parameter(type);
+            string[] propertyNames = keyName.Split('.');
+            Expression propertyAccess = param;
+            foreach (string propertyName in propertyNames)
+            {
+                PropertyInfo property = type.GetProperty(propertyName);
+                if (property == null)
+                {
+                    throw new Exception(string.Format("指定对象中不存在名称为“{0}”的属性。", propertyName));
+                }
+                type = property.PropertyType;
+                propertyAccess = Expression.MakeMemberAccess(propertyAccess, property);
+            }
+            LambdaExpression keySelector = Expression.Lambda(propertyAccess, param);
+            Cache[key] = keySelector;
+            return keySelector;
+        }
+    }
+}