本文实例讲述了C# linq查询之动态OrderBy用法。分享给大家供大家参考。具体分析如下：

groupList是原始数据集合，List<T>

sortOrder是排序类型，desc 或者asc

sortName是排序属性名称

1.使用反射。

private static object GetPropertyValue(object obj, string property) { System.Reflection.PropertyInfo propertyInfo = obj.GetType().GetProperty(property); return propertyInfo.GetValue(obj, null); } var resultList = sortOrder == "desc" ? groupList.OrderByDescending(p => GetPropertyValue(p, sortName)) : groupList.OrderBy(p => GetPropertyValue(p, sortName)); //linq方式： // var resultList1 = from p in groupList orderby GetPropertyValue(p, m.SortName) select p; if (sortOrder == "desc") resultList1 = from p in groupList orderby GetPropertyValue(p, sortName) descending select p;

2.调用AsQueryable()

将泛型 System.Collections.Generic.IEnumerable<T> 转换为泛型 System.Linq.IQueryable<T>。

var groupQueryList = groupList.AsQueryable();//here var tmpList = groupQueryList.OrderBy(sortName, sortOrder);

需要如下扩展方法：

public static IOrderedQueryable<T> OrderByDescending<T>(this IQueryable<T> source, string property) { return ApplyOrder<T>(source, property, "OrderByDescending"); } public static IOrderedQueryable<T> ThenBy<T>(this IOrderedQueryable<T> source, string property) { return ApplyOrder<T>(source, property, "ThenBy"); } public static IOrderedQueryable<T> ThenByDescending<T>(this IOrderedQueryable<T> source, string property) { return ApplyOrder<T>(source, property, "ThenByDescending"); } static IOrderedQueryable<T> ApplyOrder<T>(IQueryable<T> source, string property, string methodName) { string[] props = property.Split('.'); Type type = typeof(T); ParameterExpression arg = Expression.Parameter(type, "x"); Expression expr = arg; foreach(string prop in props) { // use reflection (not ComponentModel) to mirror LINQ PropertyInfo pi = type.GetProperty(prop); expr = Expression.Property(expr, pi); type = pi.PropertyType; } Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), type); LambdaExpression lambda = Expression.Lambda(delegateType, expr, arg); object result = typeof(Queryable).GetMethods().Single( method => method.Name == methodName && method.IsGenericMethodDefinition && method.GetGenericArguments().Length == 2 && method.GetParameters().Length == 2) .MakeGenericMethod(typeof(T), type) .Invoke(null, new object[] {source, lambda}); return (IOrderedQueryable<T>)result; }

希望本文所述对大家的C#程序设计有所帮助。