.net中JSON序列化Object指定属性两种方法

      我们在程序中经常需要对一个Object做序列化操作，有时希望对特别的属性，标记特别的名称。有几种方法可以实现：

1. 使用JSON.NET类库

    这是一个开源的类库，您可以从这里下载。它支持格式化，自定义等功能。我们通常在需要序列化属性下标记即可：

        [JsonProperty(Name = "text")]
        public string Text { get; set; }

    这个属性最后序列化的名字是text.

2. 在.net 4.0 也提供一个DataMember特性类似它，你可能在WCF中有看到过：

        [DataMember(Name = "text")]
        public string Text { get; set; }

    后面发现JSON.NET它也支持这个特性。

下面我们来看一个TreeItem的Object，为了演出这里同时支持两种方法，当然你可选择其中一种。

    [DataContract]
    public class TreeItem<TValue> : ITreeNode<TreeItem<TValue>, TValue>
    {
        private readonly List<TreeItem<TValue>> children = new List<TreeItem<TValue>>();

        /// <summary>
        /// Gets or sets the id.
        /// </summary>
        /// <value>The id.</value>
        /// <remarks>type must be string,because Jquery tree will use it replace method on it</remarks>
        [DataMember(Name = "id")]
        public string Id { get; set; }


        /// <summary>
        /// Gets or sets a value indicating whether this <see cref="TreeItem"/> is showcheck.
        /// </summary>
        /// <value><c>true</c> if showcheck; otherwise, <c>false</c>.</value>
        [DataMember(Name = "showcheck")]
        public bool Showcheck { set; get; }


        /// <summary>
        /// Gets or sets a value indicating whether this <see cref="TreeItem"/> is isexpand.
        /// </summary>
        /// <value><c>true</c> if isexpand; otherwise, <c>false</c>.</value>
        [DataMember(Name = "isexpand")]
        public bool Isexpand { set; get; }


        /// <summary>
        /// Gets or sets the checkstate.
        /// </summary>
        /// <value>The checkstate.</value>
       [DataMember(Name = "checkstate")]
        public int Checkstate { get; set; }

        /// <summary>
        ///  whether load complete（indicating whether async load data）
        ///  Suppose sync load data to node should be true
        /// </summary>
        /// <value><c>true</c> if complete; otherwise, <c>false</c>.</value>

        [DataMember(Name = "complete")]
        public bool Complete { get; set; }

        private bool _haschild;
        /// <summary>
        /// Gets a value indicating whether this instance has children.
        /// </summary>
        /// <value>
        ///     <c>true</c> if this instance has children; otherwise, <c>false</c>.
        /// </value>
        [DataMember(Name = "hasChildren")]
        public bool HasChildren
        {
            get { return (Children != null && Children.Count() > 0); }
            set { _haschild=value;}
        }

        #region ITreeNode<TreeItem<TValue>,TValue> Members

        /// <summary>
        /// Gets or sets the text.
        /// </summary>
        /// <value>The text.</value>
        [DataMember(Name = "text")]
        public string Text { get; set; }


        /// <summary>
        /// Gets or sets the value.
        /// </summary>
        /// <value>The value.</value>
        [DataMember(Name = "value")]
        public TValue Value { get; set; }

        /// <summary>
        /// Gets or sets the parent.
        /// </summary>
        /// <value>The parent.</value>
        public TreeItem<TValue> Parent { get; set; }


        /// <summary>
        /// Gets the children.
        /// </summary>
        /// <value>The children.</value>
        [JsonProperty("ChildNodes")]
        [DataMember(Name = "ChildNodes")]
        public IEnumerable<TreeItem<TValue>> Children
        {
            get { return children; }
        }

        #endregion
    }

然后用扩展方法，封装一下JSON.NET的方法：

        public static string ToJsonString<TValue>(this TreeItem<TValue> treeItem)
        {
            string sJson = JsonConvert.SerializeObject(
             treeItem);
            return "var treedata=[" + sJson + "];";
        }

        public static string ToFormatJsonString<TValue>(this TreeItem<TValue> treeItem)
        {
            string sJson = JsonConvert.SerializeObject(
                treeItem
               , Formatting.Indented,
                new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }
                );
            return "var treedata=[" + sJson + "];";
        }

下面是TestMethod:

        public void TestDataContractJsonSerializer()
        {
            var treeitem = new TreeItem<string>();
            treeitem.Id = "1";
            treeitem.Text = "Root";
            treeitem.Value = "3223";
            treeitem.Isexpand = true;
            treeitem.Showcheck = true;
            treeitem.Add(new TreeItem<string>() { Id ="2", Text = "Node2", Value = "9982",Showcheck=true,Isexpand=true,Checkstate=1 });

            using (MemoryStream stream1 = new MemoryStream())
            {

                var ser = new DataContractJsonSerializer(typeof(TreeItem<string>));
                ser.WriteObject(stream1, treeitem);
                stream1.Position = 0;
                StreamReader sr = new StreamReader(stream1);

                string mstr = "var treedata=[" + sr.ReadToEnd() + "];";

                Console.WriteLine(mstr);

                string tstr = treeitem.ToJsonString<string>();
                Console.WriteLine(tstr);

                Assert.AreEqual(tstr.Length, mstr.Length);
            }
        }

最后这个UnitTest通过了，输出结果如下：

var treedata=[{"ChildNodes":[{"ChildNodes":[],"checkstate":1,"complete":true,"hasChildren":false,"id":"2","isexpand":true,"showcheck":true,"text":"Node2","value":"9982"}],"checkstate":0,"complete":true,"hasChildren":true,"id":"1","isexpand":true,"showcheck":true,"text":"Root","value":"3223"}];
var treedata=[{"id":"1","showcheck":true,"isexpand":true,"checkstate":0,"complete":true,"hasChildren":true,"text":"Root","value":"3223","ChildNodes":[{"id":"2","showcheck":true,"isexpand":true,"checkstate":1,"complete":true,"hasChildren":false,"text":"Node2","value":"9982","ChildNodes":[]}]}];

1 passed, 0 failed, 0 skipped, took 0.86 seconds (MSTest 10.0).

你会发现它们之间区别是，顺序不同。如果您不希望引用第三方的类库，可以使用.net 4.0 提供的DataContractJsonSerializer 类。

希望对您的开发有帮助。

作者：Petter Liu
出处：http://www.cnblogs.com/wintersun/
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