实体框架句柄连接丢失

Question

我们的应用程序使用EF 5和c＃.net 4.5。由于我们的应用程序在世界各地都使用一台Cenral服务器，因此我们遇到了超时并失去与服务器的连接的问题。

目前我们捕获SaveChanges（）方法并再次尝试，直到用户取消。我们可以为代码中的各种装载做什么？

编辑：我想提出的解决方案，但我不明白它的工作正确的：

public class MyRetryStrategy : ITransientErrorDetectionStrategy 
{ 
    public bool IsTransient(Exception ex) 
    { 
     if (ex != null && ex is SqlException) 
     { 
      foreach (SqlError error in (ex as SqlException).Errors) 
      { 
       switch (error.Number) 
       { 
        case 1205: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Deadlock condition. Retrying..."); 
         return true; 

        case -2: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Timeout expired. Retrying..."); 
         return true; 

        case -1: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Timeout expired. Retrying..."); 
         return true; 
       } 
      } 
     } 

     if (ex != null && ex is EntityException) 
     { 
      ex = ex.InnerException; 
      foreach (SqlError error in (ex as SqlException).Errors) 
      { 
       switch (error.Number) 
       { 
        case 1205: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Deadlock condition. Retrying..."); 
         return true; 

        case -2: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Timeout expired. Retrying..."); 
         return true; 

        case -1: 
         System.Diagnostics.Debug.WriteLine("SQL Error: Timeout expired. Retrying..."); 
         return true; 
       } 
      } 
     } 

     // For all others, do not retry. 
     return false; 
    } 
} 

Enity框架只投我EntityExceptions所以我说第二个代码路径。

实际使用情况：

RetryPolicy policy = new RetryPolicy<MyRetryStrategy>(5, TimeSpan.FromMilliseconds(1000)); 
     policy.ExecuteAction(()=>_context.ProductStatuses.Include(x => x.Name.Translations).Load()); 

在MyRetryStrategy的IsTransient方法不会被调用，也没有重试调用。我在测试之前测试过停止Databse。

我到底做错了什么？

Answer 1

这个样本让我离开了地面。

http://hmadrigal.wordpress.com/2012/04/23/automatic-retries-using-the-transient-fault-handling-from-enterprise-libraries-entlib/

IService（下图）是你自己定制的实现。

private static void RetryPolityUsingCode(IUnityContainer container, IService service, OutputWriterService writer) 
     { 
      writer.WriteLine("Begin sample: RetryPolityUsingCode"); 
      // Define your retry strategy: retry 5 times, starting 1 second apart 
      // and adding 2 seconds to the interval each retry. 
      var retryStrategy = new Incremental(5, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(2)); 

      // Define your retry policy using the retry strategy and the Windows Azure storage 
      // transient fault detection strategy. 
      var retryPolicy = new RetryPolicy<MyRetryStrategy >(retryStrategy); 


      try 
      { 
       // Do some work that may result in a transient fault. 
       retryPolicy.ExecuteAction(service.AMethodIDefinedInMyService); 
      } 
      catch (Exception exception) 
      { 
       // All the retries failed. 
       writer.WriteLine("An Exception has been thrown:\n{0}", exception); 
      } 
      writer.WriteLine("End sample: RetryPolityUsingCode"); 
     }