Microsoft.Practices.EnterpriseLibrary.TransientFaultHandling.RetryPolicy“返回”对象

Question

我正在用TransientFaultHandling.RetryPolicy做一个小的概念验证。

在下面的代码中，我将返回一个数据集。注意，"return return；“代码在ExecuteAction块中。

    public DataSet GetADataSet()
    {
        DataSet returnDs = null;

        RetryStrategy retryStrat = new Incremental(3, TimeSpan.FromMilliseconds(500), TimeSpan.FromSeconds(1));
        RetryPolicy retryPol = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(retryStrat);

        retryPol.ExecuteAction(() =>
        {

                DatabaseProviderFactory factory = new DatabaseProviderFactory();
                Database db = factory.CreateDefault();
                DbCommand dbc = db.GetStoredProcCommand("dbo.uspGetSomeStuff");
                returnDs = db.ExecuteDataSet(dbc);
                return returnDs;

        });

        throw new InvalidOperationException("RetryPolicy let us down");
    }

当代码运行时，return被正确创建，没有错误，但是"return return；“代码不会退出该过程。而InvalidOperationException仍然会被执行/抛出。

..。

下面的代码是一种变通方法。

    public DataSet GetADataSet()
    {
        DataSet returnDs = null;

        RetryStrategy retryStrat = new Incremental(3, TimeSpan.FromMilliseconds(500), TimeSpan.FromSeconds(1));
        RetryPolicy retryPol = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(retryStrat);

        retryPol.ExecuteAction(() =>
        {

                DatabaseProviderFactory factory = new DatabaseProviderFactory();
                Database db = factory.CreateDefault();
                DbCommand dbc = db.GetStoredProcCommand("dbo.uspGetSomeStuff");
                returnDs = db.ExecuteDataSet(dbc);

        });

        if (null != returnDs)
        {
            return returnDs;
        }

        throw new InvalidOperationException("RetryPolicy let us down");
    }

.

但是，如果我有一个“void”方法，如下所示，我没有任何东西需要检查null。

    public void DoSomething()
    {
        DataSet returnDs = null;

        RetryStrategy retryStrat = new Incremental(3, TimeSpan.FromMilliseconds(500), TimeSpan.FromSeconds(1));
        RetryPolicy retryPol = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(retryStrat);

        retryPol.ExecuteAction(() =>
        {

                DatabaseProviderFactory factory = new DatabaseProviderFactory();
                Database db = factory.CreateDefault();
                DbCommand dbc = db.GetStoredProcCommand("dbo.uspDoSomething");
                db.ExecuteNonQuery(dbc);

        });

        throw new InvalidOperationException("RetryPolicy let us down");
    }

问题1:为什么"return return；“代码不退出该过程？

问题2:所以我的问题是，如何正确使用RetryPolicy，以便如果所有重试都失败，我可以抛出异常。特别是在“空DoSomething”方法的情况下。

可能是我忽略了一些愚蠢的东西。

供参考，packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="CommonServiceLocator" version="1.0" targetFramework="net40" />
  <package id="EnterpriseLibrary.Common" version="6.0.1304.0" targetFramework="net45" />
  <package id="EnterpriseLibrary.Data" version="6.0.1304.0" targetFramework="net45" />
  <package id="EnterpriseLibrary.TransientFaultHandling" version="6.0.1304.0" targetFramework="net45" />
  <package id="EnterpriseLibrary.TransientFaultHandling.Data" version="6.0.1304.1" targetFramework="net45" />
  <package id="Unity" version="2.1.505.0" targetFramework="net40" />
  <package id="Unity.Interception" version="2.1.505.0" targetFramework="net40" />
</packages>

Answer 1

我想通了。

我没有意识到ExecuteAction会有一个基于它内部代码的返回类型。

    public DataSet GetADataSet()
    {
        DataSet returnDs = null;

        var retryStrategy = new Incremental(3, TimeSpan.FromMilliseconds(500), TimeSpan.FromSeconds(1));
        var retryPolicy = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(retryStrategy);

        returnDs = retryPolicy.ExecuteAction(() =>
        {
            try
            {
                DatabaseProviderFactory factory = new DatabaseProviderFactory();
                Database db = factory.CreateDefault();
                DbCommand dbc = db.GetStoredProcCommand("dbo.uspGetSomeStuff");

                DataSet ds;
                ds = db.ExecuteDataSet(dbc);
                return ds;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        });

        return returnDs;
    }

和

    public void DoSomething()
    {
        RetryStrategy retryStrat = new Incremental(3, TimeSpan.FromMilliseconds(500), TimeSpan.FromSeconds(1));
        RetryPolicy retryPol = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(retryStrat);

        int myValue = retryPol.ExecuteAction(() =>
        {
            try
            {
                DatabaseProviderFactory factory = new DatabaseProviderFactory();
                Database db = factory.CreateDefault();
                DbCommand dbc = db.GetStoredProcCommand("dbo.uspDoSomething");
                return db.ExecuteNonQuery(dbc); /* because this returns an int, ExecuteAction return will also be an int */
            }
            catch (Exception ex)
            {
                throw ex;
            }
        });

    }