C# linq查询之动态OrderBy用法实例

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;

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

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;}