2013-11-24

[Windwos Phone]使用序列化(Serialize)做IsolatedStorage檔案儲存與讀取－使用資料合約（DataContract）Json格式

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C#

前篇介紹了使用DataContract資料合約與DataContractSerializer來序列化資料為XML格式，而在這邊我們介紹如何使用DataContract來做Json個序列化

前言

前篇介紹了使用DataContract資料合約與DataContractSerializer來序列化資料為XML格式，而在這邊我們介紹如何使用DataContract來做Json序列化

建立資料合約到資料類別

一樣建立你要序列化的資料類別與標記DataContract與DataMember，這邊還是用Student為例子

[DataContract]
    public class Student {

        public Student(int id, string name, bool isGraduated) {
            ID = id;
            Name = name;
            Graduated = isGraduated;
        }

        [DataMember(Name="StudentID")]
        public int ID { get; set; }
        [DataMember]
        public string Name { get; set; }

        [DataMember]
        public bool Graduated;

    }

Json序列化


再來，我們要增加一個Include

using System.Runtime.Serialization.Json;

這邊要稍微注意一下，如果是Windows Phone 7需要參考System.ServiceModel.Web，using　System.Runtime.Serialization.Json 才會有效

此時便會出現可以用來做Json序列化的類別，讓我們把DataContractSerializer換成DataContractJsonSerializer

string fileName;
IsolatedStorageFile recordFile;
string recordTargetFolderName;
DataContractJsonSerializer JsonSerializer;　//Json Serializer

  // 建構函式
        public MainPage()
        {
            InitializeComponent();
            recordFile = IsolatedStorageFile.GetUserStoreForApplication();
            fileName = "student.txt";
            recordTargetFolderName = "StudentRecord";
            JsonSerializer = new DataContractJsonSerializer(typeof(Student));
        }

序列化與反序列與前篇一樣

存檔序列化成Json

public void SaveData(Student saveData)
        {
            string TargetFileName = String.Format("{0}\\{1}",
                                             recordTargetFolderName, fileName);

            if (!recordFile.DirectoryExists(recordTargetFolderName))
                recordFile.CreateDirectory(recordTargetFolderName);
            try
            {
                using (var targetFile = recordFile.CreateFile(TargetFileName))
                {
                    JsonSerializer.WriteObject(targetFile, saveData);
                }
            }
            catch (Exception e)
            {
                Debug.WriteLine(e.Message);
            }
        }

反序列化讀取資料

public Student LoadData()
        {
            Student s = null;
            string TargetFileName = String.Format("{0}\\{1}",
                                              recordTargetFolderName, fileName);
            try
            {
                if (recordFile.FileExists(TargetFileName))
                {
                    using (var sourceStream = recordFile.OpenFile(TargetFileName, FileMode.Open))
                    {
                        s = (Student)JsonSerializer.ReadObject(sourceStream);
                    }
                }
            }
            catch (Exception e)
            {
                Debug.WriteLine(e.Message);

            }
            return s;
        }