LINQ to SQL query with dynamic OrderBy

public static class DynamicOrderBy
{

    public static IQueryable<TEntity> OrderBy<TEntity>(this IQueryable<TEntity> source, string orderByProperty,
                  bool desc) where TEntity : class
    {

        string command = desc ? "OrderByDescending" : "OrderBy";

        var type = typeof(TEntity);
        var property = type.GetProperty(orderByProperty);
        var parameter = System.Linq.Expressions.Expression.Parameter(type, "p");
        var propertyAccess = System.Linq.Expressions.Expression.MakeMemberAccess(parameter, property);
        var orderByExpression = System.Linq.Expressions.Expression.Lambda(propertyAccess, parameter);

        var resultExpression = 
            System.Linq.Expressions.Expression.Call(typeof(Queryable), command, new Type[] { type, property.PropertyType },
                               source.Expression, System.Linq.Expressions.Expression.Quote(orderByExpression));

        return source.Provider.CreateQuery<TEntity>(resultExpression);

    }

 

reference :

http://blogs.msdn.com/b/swiss_dpe_team/archive/2008/06/05/composable-linq-to-sql-query-with-dynamic-orderby.aspx

http://stackoverflow.com/questions/307512/how-do-i-apply-orderby-on-an-iqueryable-using-a-string-column-name-within-a-gener