使用Linq动态排序

Linq排序很方便，如果能动态创建Expression再排序就更方便了。

1. 正序还是倒序排列

   var order = typeof(Enumerable).GetMember(direction == ListSortDirection.Ascending ? "OrderBy" : "OrderByDescending")
                   .First() as MethodInfo;
   order = order.MakeGenericMethod(typeof(T), typeof(TKey));
   

2. 创建表达式

   var entityParam = Expression.Parameter(typeof(T), "item");
   Expression columnExpr = Expression.Property(entityParam, TKeyPropertyInfo);
   var delegateType = typeof(Func<,>).MakeGenericType(typeof(T), TKeyPropertyType);//属性返回值类型
   var @delegate = Expression.Lambda(delegateType, columnExpr, entityParam).Compile();
   

3. 执行

   var result = order.Invoke(null, new object[] { source, @delegate });