Mvc3+ExtJs数据格式转换（修改）

用Mvc3自带的Json（）方法返回Json类型的数据有Bug，就是对带外键的表进行数据转换时报错“序列化类型为“System.Data.Entity.DynamicProxies. 。。。”的对象时检测到循环引用”

的错误，于是我就自己写了个解决了这个问题，可能会有一些小Bug，请大牛们指出！

  /// <summary>
        /// 绑定分页数据源格式转换
        /// </summary>
        /// <typeparam name="TEntity">实体</typeparam>
        /// <param name="source">数据源</param>
        /// <param name="flag">标记（“0”只显示List:'[{},{}]'"1"显示count,+List:{count:'',list:[{},{},{}]}）</param>
        /// <param name="pageindex">页索引</param>
        /// <param name="pagesize">每页显示条数</param>
        /// <returns>字符窜</returns>
        public static String ConvertToJson<TEntity>(this IQueryable<TEntity> source, string flag, int? pageindex, int? pagesize) where TEntity : class
        {
            string sql = source.ToString();
            if (!source.ToList().Any())
            {
                if (flag.Equals("0"))
                {
                    return "[]";
                }
                return "{count:0,list:[]}";
            }
            StringBuilder builder = new StringBuilder();
            if (flag.Equals("1"))
            {
                builder.Append("{");
                builder.AppendFormat("count:{0},list:[", source.Count());
            }
            if (flag.Equals("0"))
            {
                builder.Append("[");
            }
            IQueryable<TEntity> pagedSource = source.ToPagedList<TEntity>(pageindex, pagesize);
            foreach (var obj in pagedSource)
            {
                builder.Append("{");
                PropertyInfo[] infos = obj.GetType().GetProperties();
                foreach (var item in infos)
                {
                    builder.Append(item.Name);
                    builder.Append(":");
                    if (item.PropertyType.IsGenericType && !item.PropertyType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
                    {
                        var list = Funcs.ObjectToList(item.GetValue(obj, null));
                        if (list != null)
                        {
                            builder.Append("[");
                            foreach (var child in list)
                            {
                                builder.Append("{");
                                PropertyInfo[] childinfos = child.GetType().GetProperties();
                                foreach (var chilitem in childinfos)
                                {
                                    if (!chilitem.Name.Equals(typeof(TEntity).Name))
                                    {
                                        builder.Append(chilitem.Name);
                                        builder.Append(":");
                                        if (chilitem.GetValue(child, null) == null || chilitem.GetValue(child, null).Equals(""))
                                        {
                                            builder.Append("''");
                                        }
                                        else
                                        {
                                            builder.Append("'" + chilitem.GetValue(child, null) + "'");
                                        }
                                        builder.Append(",");
                                    }
                                }
                                builder.Remove(builder.Length - 1, 1);
                                builder.Append("}");
                                builder.Append(",");
                            }
                            builder.Remove(builder.Length - 1, 1);
                            builder.Append("]");
                        }
                        else
                        {
                            builder.Append("''");
                        }
                    }
                    else
                    {
                        if (item.GetValue(obj, null) == null || item.GetValue(obj, null).Equals(""))
                        {
                            builder.Append("''");
                        }
                        else
                        {
                            builder.Append("'" + item.GetValue(obj, null) + "'");
                        }
                    }
                    builder.Append(",");
                }
                builder.Remove(builder.Length - 1, 1);
                builder.Append("}");
                builder.Append(",");
            }
            builder.Remove(builder.Length - 1, 1);
            builder.Append("]");
            if (flag.Equals("1"))
            {
                builder.Append("}");
            }

            return builder.ToString().Replace((char)13, (char)0).Replace((char)10, (char)0);
        }

 /// <summary>
        /// 分页
        /// </summary>
        /// <typeparam name="TEntity">实体</typeparam>
        /// <param name="source">数据源</param>
        /// <param name="pageindex">页索引</param>
        /// <param name="pagesize">每页显示条数</param>
        /// <returns> </returns>
        public static IQueryable<TEntity> ToPagedList<TEntity>(this  IQueryable<TEntity> source, int? pageindex, int? pagesize)
        {
            return source != null ? source.Skip(pagesize.Value * (pageindex.Value - 1)).Take(pageindex.Value * pagesize.Value) : null;
        }

     /// <summary>
        /// 取得此对象的列表
        /// </summary>
        /// <param name="target">数据源对象</param>
        /// <returns>object数组</returns>
        public static object[] ObjectToList(object target)
        {
            if (!Funcs.IsList(target)) return null;
            var count = Convert.ToInt32(target.GetType().GetProperty("Count").GetValue(target, null));
            if (!count.Equals(0))
            {
                object[] result = new object[count];
                var enumObj = target as IEnumerable<object>;
                var i = 0;
                foreach (var item in enumObj)
                {
                    result[i] = item;
                    i++;
                }
                return result;
            }
            return null;
        }