无法从 Table 存储中获取记录

Question

我有一个 table 存储 table，我想从中获取一些数据。插入和更新查询工作正常，但当我尝试 select 某些记录时遇到问题。以下是我到目前为止完成的代码：

class TransactionEntity : TableEntity
{
    public String s{ get; set; }
    public Int32 r { get; set; }
    public String e{ get; set; }
    public String t{ get; set; }
    public String l{ get; set; }
    public TransactionEntity(String id, String s, String e, String t)
    {
        this.r= 0;
        this.s= s;
        this.RowKey = id;
        this.PartitionKey = Guid.NewGuid().ToString();
        this.e= e == null ? "" : e;
        this.t= t== null ? "" : t;
    }
}

管理Table的代码：

class TableStorageManager
{
    public Boolean AddTransaction(TransactionEntity dto)
    {
        try
        {
            // Create the table client.
            CloudTableClient tableClient = new CloudTableClient(new System.Uri(ConfigurationManager.AppSettings.Get("TableStorageURI")), new StorageCredentials(ConfigurationManager.AppSettings.Get("TableStorageUser"), ConfigurationManager.AppSettings.Get("TableStoragePassword")));
            CloudTable table = tableClient.GetTableReference(ConfigurationManager.AppSettings.Get("TableStorageName"));
            table.CreateIfNotExists();
            TableOperation op = TableOperation.Insert(dto);    
            table.Execute(op);    
            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }

    public List<TransactionEntity> RetrieveAllFailedTransactions()
    {
        try
        {
            CloudTableClient tableClient = new CloudTableClient(new System.Uri(ConfigurationManager.AppSettings.Get("TableStorageURI")), new StorageCredentials(ConfigurationManager.AppSettings.Get("TableStorageUser"), ConfigurationManager.AppSettings.Get("TableStoragePassword")));
            CloudTable table = tableClient.GetTableReference(ConfigurationManager.AppSettings.Get("TableStorageName"));         
            TableQuery<TransactionEntity> query = new TableQuery<TransactionEntity>().Where("s eq '" + ConfigurationManager.AppSettings.Get("E") + "' and r lt " + ConfigurationManager.AppSettings.Get("M") + "");
            query.Take(ConfigurationTasks.GetResultLength());  
            return table.ExecuteQuery(query).ToList();
        }
        catch (Exception ex)
        {
            return null;
        }
    }

    public Boolean UpdateTransactionStatus(TransactionEntity dto)
    {
        try
        {                    
            CloudTableClient tableClient = new CloudTableClient(new System.Uri(ConfigurationManager.AppSettings.Get("TableStorageURI")), new StorageCredentials(ConfigurationManager.AppSettings.Get("TableStorageUser"), ConfigurationManager.AppSettings.Get("TableStoragePassword")));                   
            CloudTable table = tableClient.GetTableReference(ConfigurationManager.AppSettings.Get("TableStorageName"));
            dto.ETag = "*";
            TableOperation op = TableOperation.Replace(dto);
            table.Execute(op);    
            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }
}

我还更改了变量名，如果大家在阅读它们时遇到一些问题，我们深表歉意。

Answer 1

我认为您的 class 继承 TableEntity 时可能缺少 default/parameter-less 构造函数。当从 TableStorage 接收到对象时，非常需要无参数构造函数来反序列化对象。

因此，将您的 TableEntity 代码更改为：

class TransactionEntity : TableEntity
{
    public String s{ get; set; }
    public Int32 r { get; set; }
    public String e{ get; set; }
    public String t{ get; set; }
    public String l{ get; set; }
    public TransactionEntity(){//do nothing}
    public TransactionEntity(String id, String s, String e, String t)
    {
        this.r= 0;
        this.s= s;
        this.RowKey = id;
        this.PartitionKey = Guid.NewGuid().ToString();
        this.e= e == null ? "" : e;
        this.t= t== null ? "" : t;
    }
}

虽然我仍然相信，如果您能分享更多有关您在运行您的代码中遇到的任何异常的详细信息，那就太好了。另请参阅 this link 以获得有关使用 TableStorage 的更好说明。

无法从 Table 存储中获取记录

Unable to Get records from Table Storage

c#

azure

azure-table-storage