Linq动态排序扩展方法

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Linq.Expressions;

namespace Utils

{

public static class QueryExtensions

{

/// <summary>

/// Linq排序扩展方法

/// </summary>

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

/// <param name="source"></param>

/// <param name="propertyName">属性的字符串名称</param>

/// <param name="sort">方向</param>

/// <returns></returns>

public static IQueryable<T> SortBy<T>(this IQueryable<T> source, string propertyName,SortDirectionEnum sort)

{

if (source == null)

{

throw new ArgumentNullException("source");

}

if (String.IsNullOrEmpty(propertyName) || propertyName.Trim().Length == 0)

{

return source;

}

ParameterExpression parameter = Expression.Parameter(source.ElementType, String.Empty);

MemberExpression property = Expression.Property(parameter, propertyName);

LambdaExpression lambda = Expression.Lambda(property, parameter);

string methodName = (sort == SortDirectionEnum.Ascending) ? "OrderBy" : "OrderByDescending";

Expression methodCallExpression = Expression.Call(typeof(Queryable), methodName,

new Type[] { source.ElementType, property.Type },

source.Expression, Expression.Quote(lambda));

return source.Provider.CreateQuery<T>(methodCallExpression);

}

}

/// <summary>

/// 指定对项列表进行排序的方向。

/// </summary>

public enum SortDirectionEnum

{

/// <summary>

/// 从小到大排序。例如，从 A 到 Z。

/// </summary>

Ascending = 0,

/// <summary>

/// 从大到小排序。例如，从 Z 到 A。

/// </summary>

Descending = 1,

}

}

参考地址:Dynamic Sorting with Linq