细节见差别！从构架谈AzureTable开发-技术开发专区

细节见差别！从构架谈AzureTable开发

作者：蒋建华编辑：胡铭娅 2010-07-12 00:05 IT168网站原创

　　在这里由于篇幅，我们只是介绍核心代码的编写。要使用Windows Azure Table，就需要创建相关的实体类，本案例中的实体类是ImageEntity，图片实体类，这个实体类是需要继承TableServiceEntity的，代码如下：

public class ImageEntity:TableServiceEntity
    {
        public ImageEntity()
        {
            PartitionKey = DateTime.UtcNow.ToString("yyyyMMdd");
            RowKey = string.Format("{0:10}_{1}", DateTime.MaxValue.Ticks -
            DateTime.Now.Ticks, Guid.NewGuid());
        }
        public Uri FileUri { get; set; }
        public string FileName { get; set; }
        public long Length { get; set; }
        public string FolderName { get; set; }
        public bool IsReadOnly { get; set; }
        public bool IsExists { get; set; }
        public string FullFileName { get; set; }
        public string ExtendName { get; set; }
        public string CreatorName { get; set; }
        public DateTime CreateTime { get; set; }
    }

　　创建完图片实体类后，需要接着创建ImageContext，这个类是通过上下文环境对实体进行添加、修改、查询的类，此类需要继承自TableServiceContext，代码如下：

public class ImageContext:TableServiceContext
    {
        private const string ENTITY_NAME = "imageentity";

        public ImageContext(string baseAddress, StorageCredentials credentials)
            : base(baseAddress, credentials)
        {
            CloudTableClient.CreateTablesFromModel(typeof(ImageContext), baseAddress, credentials);
        }
        public IQueryable<ImageEntity> ImageEntity
        {
            get { return CreateQuery<ImageEntity>(ENTITY_NAME); }
        }
        /// <summary>
        /// Add object to table
        /// </summary>
        /// <param name="data">ImageEntity object to add</param>
        public void Add(ImageEntity data)
        {
            AddObject(ENTITY_NAME, data);
            SaveChanges();
        }
        /// <summary>
        /// Update object
        /// </summary>
        /// <param name="original">Original ImageEntity object</param>
        /// <param name="data">Updated object</param>
        public void Update(ImageEntity original, ImageEntity data)
        {
            original.CreateTime = data.CreateTime;
            original.CreatorName = data.CreatorName;
            original.ExtendName = data.ExtendName;
            original.FileName = data.FileName;
            original.FileUri = data.FileUri;
            original.FolderName = data.FolderName;
            original.FullFileName = data.FullFileName;
            original.IsExists = data.IsExists;
            original.IsReadOnly = data.IsReadOnly;
            original.Length = data.Length;

            UpdateObject(original);

            SaveChanges();
        }
    }

　　有关实体的类编写完成后，就对Table的操作的类(类名：StorageTable)代码进行编写，主要代码这里列出了对添加实体到Table的方法：

/// <summary>
        /// Add object to table
        /// </summary>
        /// <param name="data">ImageEntity object to add</param>
        public void Add(ImageEntity data)
        {
            Context.Add(data);
        }

这里的Context就是实体操作类的一个实例。

private ImageContext Context
        {
            get { return new ImageContext(Account.TableEndpoint.AbsoluteUri, Account.Credentials); }
        }

第1页：开发环境第2页：应用与案例第3页：代码的编写第4页：Web Role（用户UI层）代码第5页：设置服务定义和服务配置文件第6页：调试运行及总结

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