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最近在脑补Expression Tree 系列 http://www.cnblogs.com/Ninputer/archive/2009/08/28/expression_tree1.html
然后发现 http://www.codeproject.com/Articles/235860/Expression-Tree-Basics 写得相当不错。
所以就稍微改动，实现了如下代码
public static IEnumerable OrderBy(this IEnumerable source, string propertyName, bool desc = false)
{
if (source == null) throw new ArgumentNullException("source");
if (string.IsNullOrEmpty(propertyName)) return source;
var item = Expression.Parameter(typeof(T), "item");
var prop = Expression.Property(item, propertyName);
var keySelector = Expression.Lambda(prop, item);
var param = Expression.Parameter(typeof(IEnumerable), "source");
var orderBy = Expression.Call(typeof(Enumerable), (desc ? "OrderByDescending" : "OrderBy"), new[] { typeof(T), prop.Type }, param, keySelector);
var sorter = Expression.Lambda, IEnumerable>>(orderBy, param);
return sorter.Compile()(source);
}
使用方法：
public class Student
{
public string Name { get; set; }
public int Age { get; set; }
public Student(string name, int age)
{
this.Name = name;
this.Age = age;
}
public override string ToString()
{
return string.Format("Name:{0}\t Age:{1}", this.Name, this.Age);
}
}
static void Main(string[] args)
{
List list = new List
{
new Student("张三",13),
new Student("李四",15),
new Student("王五",14)
};
var sortList = list.OrderBy("Age");
foreach (var item in sortList)
{
Console.WriteLine(item.ToString());
}
Console.WriteLine("\nDesc:\n");
var sortList2 = list.OrderBy("Age", true);
foreach (var item in sortList2)
{
Console.WriteLine(item.ToString());
}
}
通过Expression 动态实现IEnumerable<T> CustomOrderBy
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原文地址：http://www.cnblogs.com/inobody/p/5933157.html
