包装APM样式时将“状态”传递给任务并行库

Question

我想将状态传递给以下扩展方法：

     // Overload 2
    public static Task<TableQuerySegment<T>> ExecuteQuerySegmentedAsync<T> (this CloudTable tbl, TableQuery<T> query, TableContinuationToken continuationToken, CancellationToken token) where T : ITableEntity, new()
    {
        return tbl.ExecuteQuerySegmentedAsync<T>(query, continuationToken, null, null, token);
    }

    // Overload 5
    public static Task<TableQuerySegment<TElement>> ExecuteQuerySegmentedAsync<TElement>(this CloudTable tbl, TableQuery<TElement> query, TableContinuationToken continuationToken, TableRequestOptions opt, OperationContext ctx, CancellationToken token) where TElement : ITableEntity, new()
    {
        ICancellableAsyncResult result = null;

        if (opt == null && ctx == null)
            result = tbl.BeginExecuteQuerySegmented<TElement>(query, continuationToken, null, tbl);
        else
            result = tbl.BeginExecuteQuerySegmented<TElement>(query, continuationToken, opt, ctx, null, tbl);

        var cancellationRegistration = token.Register(result.Cancel);

        return Task.Factory.FromAsync(result, iAsyncResult =>
        {
            CloudTable currentTable = iAsyncResult.AsyncState as CloudTable;

            cancellationRegistration.Dispose(); // todo: handle cleanup of this (deregistration)
            return currentTable.EndExecuteQuerySegmented<TElement>(result);
        });
    }

    // Overload 3
    public static Task<TableQuerySegment<R>> ExecuteQuerySegmentedAsync<T, R>(this CloudTable tbl, TableQuery<T> query, EntityResolver<R> resolver, TableContinuationToken continuationToken, CancellationToken token) where T : ITableEntity, new()
    {
        return tbl.ExecuteQuerySegmentedAsync<T, R>(query, resolver, continuationToken, null, null, token);
    }

    // Overload 6
    public static Task<TableQuerySegment<R>> ExecuteQuerySegmentedAsync<TElement, R>(this CloudTable tbl, TableQuery<TElement> query, EntityResolver<R> resolver, TableContinuationToken continuationToken, TableRequestOptions opt, OperationContext ctx, CancellationToken token) where TElement : ITableEntity, new()
    {
        ICancellableAsyncResult result = null;

        if (opt == null && ctx == null)
            result = tbl.BeginExecuteQuerySegmented<TElement, R>(query, resolver, continuationToken, null, null);
        else
            result = tbl.BeginExecuteQuerySegmented<TElement, R>(query, resolver, continuationToken, opt, ctx, null, null);

        var cancellationRegistration = token.Register(result.Cancel);

        return Task.Factory.FromAsync(result, iAsyncResult =>
        {
            CloudTable currentTable = iAsyncResult.AsyncState as CloudTable;

            cancellationRegistration.Dispose(); // todo: handle cleanup of this (deregistration)
            return currentTable.EndExecuteQuerySegmented<R>(result);
        });
    }

所以我可以这样调用代码

            // prepare the query
            trustsInBatchesOf100 = tableSymmetricKeys.ExecuteQuerySegmentedAsync(query, token, opt, ctx, cancelToken);

            // my state
            object mystate  = trustsInBatchesOf100.AsyncState;

我一直在努力弄清楚如何修改扩展方法以包括stateObject 。 困难在于我在TaskFactory.FromAsync中找到正确的重载，并在扩展方法中正确实现了它。

题

如何修改上述扩展方法以正确接受状态参数？

更多源代码

    private CloudTableClient tableClient;
    private CloudStorageAccount account;
    private TableRequestOptions opt;

    List<Task<TableResult>> AllRunningTasks = null;

    public async Task GetTrustsAndValues(string thingToSearchFor,string trustStartingPoint, 
        int depth,
        TableQuery query,                             
         OperationContext ctx, CancellationToken cancelToken)
    {
        TrustState asyncState = new TrustState() { ThingToSearchFor = thingToSearchFor, TimeStarted = DateTime.UtcNow };

        var ret = new TrustTree<string>(thingToSearchFor, "start", 10);


        CloudTableClient client = account.CreateCloudTableClient();
        CloudTable tableSymmetricKeys = client.GetTableReference("SymmetricKeys5"); 

       // List<Task> taskList = new List<Task>();

        TableContinuationToken token = new TableContinuationToken() { };
        Task<TableQuerySegment<DynamicTableEntity>> trustsInBatchesOf100 = null;

        while (true)
        {
            // prepare the query
            trustsInBatchesOf100 = tableSymmetricKeys.ExecuteQuerySegmentedAsync(query, token, opt, ctx, cancelToken);

            object mystate  = trustsInBatchesOf100.AsyncState;

            // Run the method
            trustsInBatchesOf100.Wait();

            // Create tasks for each of the 100 domains found.
            IEnumerable<Task<TableResult>> getTrustDataQuery =
                          from domainData in trustsInBatchesOf100.Result select QueryPartnerForData(ref ret,domainData, thingToSearchFor, client, cancelToken);

            // Save the count of lookups as appropriate  
            asyncState.RunningDirectQueries = getTrustDataQuery.Count();

            // Run up to 100 lookups on those domains.
            var runningTasks = getTrustDataQuery.ToList();

            // Add running tasks to the full compilation of running tasks
            AllRunningTasks.AddRange(runningTasks );

            // Prepare for next iteration or quit
            if (token == null)
            {
                break;
            }
            else
            {
                token = trustsInBatchesOf100.Result.ContinuationToken;

                // todo: persist token  token.WriteXml()
            }
        }
    }



    private static Task<TableResult> QueryPartnerForData(ref  TrustTree<string> tree, DynamicTableEntity domainData, string thingToSearchFor, CloudTableClient client, CancellationToken cancelToken)
    {
        // Create the table client.
        CloudTable tableDirectQuery = client.GetTableReference(String.Format("{0}_FW", domainData.RowKey));

        // Retrieve the entity with partition key of "Smith" and row key of "Jeff"
        TableOperation tableOperation = TableOperation.Retrieve(domainData.RowKey, thingToSearchFor);

        // Retrieve entity asynchronously
        return tableDirectQuery.ExecuteAsync(tableOperation, cancelToken);
    }

    public async void SaveCompletedQueriesTo()
    {
        while (AllRunningTasks.Count > 0)
        {
            // Identify the first task that completes.
            Task<TableResult> firstFinishedTask = await Task.WhenAny(AllRunningTasks);

            // ***Remove the selected task from the list so that you don't
            // process it more than once.
            AllRunningTasks.Remove(firstFinishedTask);

            // Await the completed task.
            var taskOfTableResult = await firstFinishedTask;

            //todo: asyncState: need to know what the 
            // - target to save to is.
        }

        // TODO: if all tasks have completed then update 
    }

Answer 1

您是否看到过Microsoft.WindowsAzure.StorageClient.Async项目？ （也在NuGet上可用 ）。 它可能提供了一些想法，或者已经解决了您的问题。 否则，请在正确完成后考虑将更改添加到该项目。