BackupTableRange建立了一个会扫描指定密钥范围的查询，然后援引下列BackupToContainer。我们使用 BackupEntity类来读取结果。BackupEntity保存了一个内部XElement，XElement名为EntryElement，它将接收到的一个用于实体数据的原始OData XML保存在查询响应中。为了掌握这个原始数据，我们可以使用所示代码中的ReadingEntity事件。ResolveType代表用来提供类型名称，而WCF数据服务客户会使用此类型名称。

/// /// Create a query that will scan the assigned range and save it to a blob in the given container /// /// /// /// /// /// private static void BackupTableRange( CloudTableClient tableClient, CloudBlobContainer container, string tableName, PartitionKeyRange range, string backupId) {         TableServiceContext context = tableClient.GetDataServiceContext();         context.MergeOption = MergeOption.NoTracking;         context.ResolveType = TableBackup.ResolveType;         context.ReadingEntity += new EventHandler(TableBackup.OnReadingEntity);         context.RetryPolicy = RetryPolicies.RetryExponential(5, RetryPolicies.DefaultClientBackoff);                 var query = from entity in context.CreateQuery(tableName) select entity;         if (range.Min != null)         {             query = query.Where(entity => entity.PartitionKey.CompareTo(range.Min) >= 0);         }           if (range.Max != null)         {             query = query.Where(entity => entity.PartitionKey.CompareTo(range.Max) < 0);         }                 CloudTableQuery cloudQuery = new CloudTableQuery((DataServiceQuery)query);           BackupToContainer(container, cloudQuery, backupId, range); }   /// /// Entities used for backup/restore /// [DataServiceKey("PartitionKey", "RowKey")] public class BackupEntity {     public string PartitionKey { get; set; }       public string RowKey { get; set; }       ///     /// Used during restore to store the entry element.     ///     internal XElement EntryElement { get; set; } }   static void OnReadingEntity(object sender, ReadingWritingEntityEventArgs args) {      BackupEntity entity = args.Entity as BackupEntity;      entity.EntryElement = args.Data; }   static Type ResolveType(string entityName) {         return typeof(BackupEntity); }

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