"Fluent methods may not be invoked on a Query created via CloudTable.CreateQuery<T>()" exception

Question

What does the following exception means?

System.NotSupportedException was unhandled Message: An unhandled exception of type 'System.NotSupportedException' occurred in mscorlib.dll Additional information: Fluent methods may not be invoked on a Query created via CloudTable.CreateQuery()

It does not show the code throwing the exception so I don't know how to start debugging it.

Result StackTrace: at System.Web.Http.ApiController.d__1.MoveNext() --- End of inner exception stack trace --- at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions) at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task1.get_Result() at TestFramework.ExecuteRequest(HttpRequestMessage request) in d:\ at TestFramework.Post(String uri, Object tniObject) in d:\ at TestFramework.PostCall(String uri, Object o) in d:\ at TestFramework.MyMethod(String one, String two, MyStruct three) in d:\ ... (Removed for privacy)

I believe the problem is in the following instruction.

string queryString = TableQuery.CombineFilters(TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, myId),
                                               TableOperators.And,
                                               TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.Equal, number));
var theQuery = MyTable.CreateQuery<MyEntity>().Where(queryString);

can I use theQuery then to perform a segmented async query?

var returnList = new List<T>();
TableQuerySegment<T> querySegment = null;

querySegment = await theQuery.AsTableQuery().ExecuteSegmentedAsync(null);

// The query could potentially return more than one object
returnList.AddRange(querySegment);

Well, changing the CreateQuery method call to the following code made the exception to go away.

 var query = new TableQuery<TenantTNEntity>().Where(queryString);

The exception I get now says:

Result Message: Test method MyMethod threw exception:

System.AggregateException: One or more errors occurred. ---> System.InvalidOperationException: Unknown Table. The TableQuery does not have an associated CloudTable Reference. Please execute the query via the CloudTable ExecuteQuery APIs.

Pantisocracy

What's the stack trace? – Coursing

@Coursing stack trace provided – Pantisocracy

What version of Azure client library are you using? – Deform

@Deform Microsoft.WindowsAzure.StorageClient version 1.7.0.0 – Pantisocracy

Answer 1

I don't know if this is specifically your problem, but it certainly was mine, and it took me a while to figure out. For reasons that I'm not entirely clear on, the Azure team has provided two different and incompatible ways to execute queries - and although they're incompatible at runtime, the Azure team has helpfully (not!) made sure that they have compatible signatures at compile time.

See the difference between the "Fluent" and "IQueryable" modes described here:

http://blogs.msdn.com/b/windowsazurestorage/archive/2013/09/07/announcing-storage-client-library-2-1-rtm.aspx

In other words, both of these will compile and run and do more or less the same thing:

var fluentQuery = new TableQuery<T>().Where(filter);
var fluentResult = Table.ExecuteQuery(fluentQuery);

var iQueryableQuery= from ent in Table.CreateQuery<T>() 
                     where ent.PartitionKey == "some value" 
                     select ent;
var iQueryableResult = iQueryableQuery.AsTableQuery().Execute();

But while this one will compile just fine, it will blow up at runtime with the System.NotSupportedException that you (and I) ran into.

var fluentQuery2 = Table.CreateQuery<T>().Where(filter);
var fluentResult2 = fluentQuery2.Execute();

I'm sure that the folks at MS had some good reason for this particular violation of the Principle of Least Astonishment - they're not idiots - but it certainly remains the case that this behavior is, shall we say, unusual.

Lissettelissi

For those of us familiar with entityframework, you cannot just write the IQueryable statement and call one of the enumeration methods (e.g. ToList) for this to work. You have to call AsTableServiceQuery().Execute() on the IQueryable before you enumerate. – Singlehandedly

@Singlehandedly Where do you get AsTableServiceQuery() extension from? I tried utilizing this but couldn't find it. – Fossette

@Fossette Microsoft.WindowsAzure.StorageClient (which is both the name of namespace and the dll) – Singlehandedly

what version? 6.1.0 of WindowsAzure.Storage is what I'm using nuget.org/packages/WindowsAzure.Storage/6.1.0 StorageClient doesn't exist (nor Storage.Client) – Fossette

@Fossette Sorry for the late response, it's part of the Azure SDK azure.microsoft.com/en-us/downloads I don't think it's available from nuget (which is strange) – Singlehandedly

hm. strange. no worries, we're doing it another way. also, it looks obsolete msdn.microsoft.com/en-us/library/azure/jj717613.aspx – Fossette

Exactly! I was struggling to find out the reason. In case you want to use it async use ExecuteQuerySegmentedAsync. Thanks @Ken Smith – Planetary

Thanks for the link. My problem was trying to call take directly on the queryable. Adding a .Select(c => c) before the take allowed the query to complete. – Turnip

Almost gave up on this until I saw this post. Thx! – Equiangular

Answer 2

Adding ".AsQueryable()" before ".Take(x)" will make it run

Amentia