I have a wired problem in my ASP.NET MVC application using NHibernate.
There is a virutal method named IsLeaderBanker(IbEmployee banker) in my domain model. The impelementaion is like this:
public virtual bool IsLeaderBanker(IbEmployee banker)
{
return GetLeaderBankers().Any(lb => lb.Id == banker.Id);
}
It is simple and smooth. However, Nhibernate throws an Exception when initializing SessionStorage.
The entity '<>c__DisplayClass9' doesn't have an Id mapped. Use the Id method to map your identity property. For example: Id(x => x.Id).
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: FluentNHibernate.Visitors.ValidationException: The entity '<>c__DisplayClass9' doesn't have an Id mapped. Use the Id method to map your identity property. For example: Id(x => x.Id).
Source Error:
Line 144: storage = new WebSessionStorage(this);
Line 145: NHibernateInitializer.Instance().InitializeNHibernateOnce(
Line 146: () => NHibernateSession.Init(storage,
Line 147: new[] { Server.MapPath(#"~/bin/IB.Oss.Dal") },
Line 148: AutoPersistenceModelGenerator.Generate(
After tried quite a lot of guesses and tests, I found it is the LINQ Any method made it crash. Which is, if I rewrite it like this:
public virtual bool IsLeaderBanker(IbEmployee banker)
{
var result = GetLeaderBankers();
foreach (var b in result)
{
if (b.Id == banker.Id)
{
return true;
}
}
return false;
}
Everything works. This is the same logic and Reshaper suggests me to change it to LINQ. Why the Any method breaks NHibernate? I use Where and Select many times and they all work fine.
The Nhibernate Version is 3.3.2 in my application.
Try this:
public virtual bool IsLeaderBanker(IbEmployee banker)
{
var id = banker.Id;
return GetLeaderBankers().Any(lb => lb.Id == id);
}
Related
I have a project where the front-end JavaScript specifies a list of columns to order by.
Then in the back-end I have multi-layer application. Typical scenario
Service layer (the service models' (DTO) properties match whatever the client-side wants to order by)
Domain layer (it exposes repository interfaces to access persisted objects)
ORM layer (it implements the repository and it uses Entity Framework 7 (a.k.a Entity Framework Core) to access a SQL Server database)
Please note that System.Linq.Dynamic IS NOT supported for DNX Core v5.0 or .NET Platform v5.4 so I cannot use that library.
I have the following implementation in my Things repository:
public async Task<IEnumerable<Thing>> GetThingsAsync(IEnumerable<SortModel> sortModels)
{
var query = GetThingsQueryable(sortModels);
var things = await query.ToListAsync();
return things;
}
private IQueryable<Thing> GetThingsQueryable(IEnumerable<SortModel> sortModels)
{
var thingsQuery = _context.Things
.Include(t => t.Other)
.Where(t => t.Deleted == false);
// this is the problematic area as it does not return a valid queryable
string orderBySqlStatement = GetOrderBySqlStatement(sortModels);
thingsQuery = thingsQuery.FromSql(orderBySqlStatement);
return thingsQuery ;
}
/// this returns something like " order by thingy1 asc, thingy2 desc"
private string GetOrderBySqlStatement(IEnumerable<SortModel> sortModels)
{
IEnumerable<string> orderByParams = sortModels.Select(pair => { return pair.PairAsSqlExpression; });
string orderByParamsConcat = string.Join(", ", orderByParams);
string sqlStatement = orderByParamsConcat.Length > 1 ? $" order by {orderByParamsConcat}" : string.Empty;
return sqlStatement;
}
and this is the object that contains a column name and a order by direction (asc or desc)
public class SortModel
{
public string ColId { get; set; }
public string Sort { get; set; }
public string PairAsSqlExpression
{
get
{
return $"{ColId} {Sort}";
}
}
}
This approach tries to mix a SQL statement with whatever Entity creates for the previous queryable. But I get a:
Microsoft.Data.Entity.Query.Internal.SqlServerQueryCompilationContextFactory:Verbose: Compiling query model: 'from Thing t in {value(Microsoft.Data.Entity.Query.Internal.EntityQueryable`1[MyTestProj.Data.Models.Thing]) => AnnotateQuery(Include([t].DeparturePort)) => AnnotateQuery(Include([t].ArrivalPort)) => AnnotateQuery(Include([t].Consignments))} where (([t].CreatorBusinessId == __businessId_0) AndAlso (Convert([t].Direction) == __p_1)) select [t] => AnnotateQuery(QueryAnnotation(FromSql(value(Microsoft.Data.Entity.Query.Internal.EntityQueryable`1[MyTestProj.Data.Models.Thing]), " order by arrivalDate asc, arrivalPortCode asc", []))) => Count()'
Microsoft.Data.Entity.Query.Internal.SqlServerQueryCompilationContextFactory:Verbose: Optimized query model: 'from Thing t in value(Microsoft.Data.Entity.Query.Internal.EntityQueryable`1[MyTestProj.Data.Models.Thing]) where (([t].CreatorBusinessId == __businessId_0) AndAlso (Convert([t].Direction) == __p_1)) select [t] => Count()'
Microsoft.Data.Entity.Query.Internal.QueryCompiler:Error: An exception occurred in the database while iterating the results of a query.
System.InvalidOperationException: The Include operation is not supported when calling a stored procedure.
at Microsoft.Data.Entity.Query.ExpressionVisitors.RelationalEntityQueryableExpressionVisitor.VisitEntityQueryable(Type elementType)
at Microsoft.Data.Entity.Query.ExpressionVisitors.EntityQueryableExpressionVisitor.VisitConstant(ConstantExpression constantExpression)
at System.Linq.Expressions.ConstantExpression.Accept(ExpressionVisitor visitor)
at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
at Microsoft.Data.Entity.Query.ExpressionVisitors.ExpressionVisitorBase.Visit(Expression expression)
at Microsoft.Data.Entity.Query.EntityQueryModelVisitor.ReplaceClauseReferences(Expression expression, IQuerySource querySource, Boolean inProjection)
at Microsoft.Data.Entity.Query.EntityQueryModelVisitor.CompileMainFromClauseExpression(MainFromClause mainFromClause, QueryModel queryModel)
at Microsoft.Data.Entity.Query.RelationalQueryModelVisitor.CompileMainFromClauseExpression(MainFromClause mainFromClause, QueryModel queryModel)
at Microsoft.Data.Entity.Query.EntityQueryModelVisitor.VisitMainFromClause(MainFromClause fromClause, QueryModel queryModel)
at Remotion.Linq.Clauses.MainFromClause.Accept(IQueryModelVisitor visitor, QueryModel queryModel)
at Remotion.Linq.QueryModelVisitorBase.VisitQueryModel(QueryModel queryModel)
at Microsoft.Data.Entity.Query.EntityQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
at Microsoft.Data.Entity.Query.RelationalQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
at Microsoft.Data.Entity.Query.Internal.SqlServerQueryModelVisitor.VisitQueryModel(QueryModel queryModel)
at Microsoft.Data.Entity.Query.EntityQueryModelVisitor.CreateAsyncQueryExecutor[TResult](QueryModel queryModel)
at Microsoft.Data.Entity.Storage.Database.CompileAsyncQuery[TResult](QueryModel queryModel)
at Microsoft.Data.Entity.Query.Internal.QueryCompiler.<>c__DisplayClass19_0`1.<CompileAsyncQuery>b__0()
at Microsoft.Data.Entity.Query.Internal.CompiledQueryCache.GetOrAddAsyncQuery[TResult](Object cacheKey, Func`1 compiler)
at Microsoft.Data.Entity.Query.Internal.QueryCompiler.CompileAsyncQuery[TResult](Expression query)
at Microsoft.Data.Entity.Query.Internal.QueryCompiler.ExecuteAsync[TResult](Expression query, CancellationToken cancellationToken)
Exception thrown: 'System.InvalidOperationException' in EntityFramework.Core.dll
Exception thrown: 'System.InvalidOperationException' in mscorlib.ni.dll
Exception thrown: 'System.InvalidOperationException' in mscorlib.ni.dll
Microsoft.AspNet.Diagnostics.Entity.DatabaseErrorPageMiddleware:Verbose: System.InvalidOperationException occurred, checking if Entity Framework recorded this exception as resulting from a failed database operation.
Microsoft.AspNet.Diagnostics.Entity.DatabaseErrorPageMiddleware:Verbose: Entity Framework recorded that the current exception was due to a failed database operation. Attempting to show database error page.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Opening connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Closing connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Opening connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Closing connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Opening connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.RelationalCommandBuilderFactory:Information: Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT OBJECT_ID(N'__EFMigrationsHistory');
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Closing connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.SqlServerConnection:Verbose: Opening connection 'Server=(localdb)\mssqllocaldb;Database=SpeediCargo;Trusted_Connection=True;MultipleActiveResultSets=true'.
Microsoft.Data.Entity.Storage.Internal.RelationalCommandBuilderFactory:Information: Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
It seems it's not possible to mix SQL for the order by part with the rest of the linq query?
Or the problem is that I am not prefixing the columns with the [t] and Entity is unable to understand what are those columns?
In any case, is there any example or recommendation on how to achieve what I want with Entity 7 and the core .net framework?
FromSql definitely cannot be used to mix SQL. So as usual with dynamic queries, you have to resort to System.Linq.Expressions.
For instance, something like this:
public static class QueryableExtensions
{
public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, IEnumerable<SortModel> sortModels)
{
var expression = source.Expression;
int count = 0;
foreach (var item in sortModels)
{
var parameter = Expression.Parameter(typeof(T), "x");
var selector = Expression.PropertyOrField(parameter, item.ColId);
var method = string.Equals(item.Sort, "desc", StringComparison.OrdinalIgnoreCase) ?
(count == 0 ? "OrderByDescending" : "ThenByDescending") :
(count == 0 ? "OrderBy" : "ThenBy");
expression = Expression.Call(typeof(Queryable), method,
new Type[] { source.ElementType, selector.Type },
expression, Expression.Quote(Expression.Lambda(selector, parameter)));
count++;
}
return count > 0 ? source.Provider.CreateQuery<T>(expression) : source;
}
}
And then:
var thingsQuery = _context.Things
.Include(t => t.Other)
.Where(t => t.Deleted == false)
.OrderBy(sortModels);
Currently I'm developing an OAuth2 authorization server using DotNetOpenAuth CTP version. My authorization server is in asp.net MVC3, and it's based on the sample provided by the library. Everything works fine until the app reaches the point where the user authorizes the consumer client.
There's an action inside my OAuth controller which takes care of the authorization process, and is very similar to the equivalent action in the sample:
[Authorize, HttpPost, ValidateAntiForgeryToken]
public ActionResult AuthorizeResponse(bool isApproved)
{
var pendingRequest = this.authorizationServer.ReadAuthorizationRequest();
if (pendingRequest == null)
{
throw new HttpException((int)HttpStatusCode.BadRequest, "Missing authorization request.");
}
IDirectedProtocolMessage response;
if (isApproved)
{
var client = MvcApplication.DataContext.Clients.First(c => c.ClientIdentifier == pendingRequest.ClientIdentifier);
client.ClientAuthorizations.Add(
new ClientAuthorization
{
Scope = OAuthUtilities.JoinScopes(pendingRequest.Scope),
User = MvcApplication.LoggedInUser,
CreatedOn = DateTime.UtcNow,
});
MvcApplication.DataContext.SaveChanges();
response = this.authorizationServer.PrepareApproveAuthorizationRequest(pendingRequest, User.Identity.Name);
}
else
{
response = this.authorizationServer.PrepareRejectAuthorizationRequest(pendingRequest);
}
return this.authorizationServer.Channel.PrepareResponse(response).AsActionResult();
}
Everytime the program reaches this line:
this.authorizationServer.Channel.PrepareResponse(response).AsActionResult();
The system throws an exception which I have researched with no success. The exception is the following:
Only parameterless constructors and initializers are supported in LINQ to Entities.
The stack trace: http://pastebin.com/TibCax2t
The only thing I've done differently from the sample is that I used entity framework's code first approach, an I think the sample was done using a designer which autogenerated the entities.
Thank you in advance.
If you started from the example, the problem Andrew is talking about stays in DatabaseKeyNonceStore.cs. The exception is raised by one on these two methods:
public CryptoKey GetKey(string bucket, string handle) {
// It is critical that this lookup be case-sensitive, which can only be configured at the database.
var matches = from key in MvcApplication.DataContext.SymmetricCryptoKeys
where key.Bucket == bucket && key.Handle == handle
select new CryptoKey(key.Secret, key.ExpiresUtc.AsUtc());
return matches.FirstOrDefault();
}
public IEnumerable<KeyValuePair<string, CryptoKey>> GetKeys(string bucket) {
return from key in MvcApplication.DataContext.SymmetricCryptoKeys
where key.Bucket == bucket
orderby key.ExpiresUtc descending
select new KeyValuePair<string, CryptoKey>(key.Handle, new CryptoKey(key.Secret, key.ExpiresUtc.AsUtc()));
}
I've resolved moving initializations outside of the query:
public CryptoKey GetKey(string bucket, string handle) {
// It is critical that this lookup be case-sensitive, which can only be configured at the database.
var matches = from key in db.SymmetricCryptoKeys
where key.Bucket == bucket && key.Handle == handle
select key;
var match = matches.FirstOrDefault();
CryptoKey ck = new CryptoKey(match.Secret, match.ExpiresUtc.AsUtc());
return ck;
}
public IEnumerable<KeyValuePair<string, CryptoKey>> GetKeys(string bucket) {
var matches = from key in db.SymmetricCryptoKeys
where key.Bucket == bucket
orderby key.ExpiresUtc descending
select key;
List<KeyValuePair<string, CryptoKey>> en = new List<KeyValuePair<string, CryptoKey>>();
foreach (var key in matches)
en.Add(new KeyValuePair<string, CryptoKey>(key.Handle, new CryptoKey(key.Secret, key.ExpiresUtc.AsUtc())));
return en.AsEnumerable<KeyValuePair<string,CryptoKey>>();
}
I'm not sure that this is the best way, but it works!
It looks like your ICryptoKeyStore implementation may be attempting to store CryptoKey directly, but it's not a class that is compatible with the Entity framework (due to not have a public default constructor). Instead, define your own entity class for storing the data in CryptoKey and your ICryptoKeyStore is responsible to transition between the two data types for persistence and retrieval.
I am in the middle of a refactoring cycle where I converted some extension methods that used to look like this:
public static IQueryable<Family> FilterOnRoute(this IQueryable<Family> families, WicRoute route)
{
return families.Where(fam => fam.PODs
.Any(pod => pod.Route.RouteID == route.RouteID));
}
to a more fluent implementation like this:
public class SimplifiedFamilyLinqBuilder
{
private IQueryable<Family> _families;
public SimplifiedFamilyLinqBuilder Load(IQueryable<Family> families)
{
_families = families;
return this;
}
public SimplifiedFamilyLinqBuilder OnRoute(WicRoute route)
{
_families = _families.Where(fam => fam.PODs
.Any(pod => pod.Route.RouteID == route.RouteID));
return this;
}
public IQueryable<Family> AsQueryable()
{
return _families;
}
}
which I can call like this: (note this is using Linq-to-Nhibernate)
var families =
new SimplifiedFamilyLinqBuilder()
.Load(session.Query<Family>())
.OnRoute(new WicRoute() {RouteID = 1})
.AsQueryable()
.ToList();
this produces the following SQL which is fine with me at the moment: (of note is that the above Linq is being translated to a SQL Query)
select ... from "Family" family0_
where exists (select pods1_.PODID from "POD" pods1_
inner join Route wicroute2_ on pods1_.RouteID=wicroute2_.RouteID
where family0_.FamilyID=pods1_.FamilyID
and wicroute2_.RouteID=#p0);
#p0 = 1
my next effort in refactoring is to move the query part that deals with the child to another class like this:
public class SimplifiedPODLinqBuilder
{
private IQueryable<POD> _pods;
public SimplifiedPODLinqBuilder Load(IQueryable<POD> pods)
{
_pods = pods;
return this;
}
public SimplifiedPODLinqBuilder OnRoute(WicRoute route)
{
_pods = _pods.Where(pod => pod.Route.RouteID == route.RouteID);
return this;
}
public IQueryable<POD> AsQueryable()
{
return _pods;
}
}
with SimplifiedFamilyLinqBuilder changing to this:
public SimplifiedFamilyLinqBuilder OnRoute(WicRoute route)
{
_families = _families.Where(fam =>
_podLinqBuilder.Load(fam.PODs.AsQueryable())
.OnRoute(route)
.AsQueryable()
.Any()
);
return this;
}
only I now get this error:
Remotion.Linq.Parsing.ParserException : Cannot parse expression 'value(Wic.DataTests.LinqBuilders.SimplifiedPODLinqBuilder)' as it has an unsupported type. Only query sources (that is, expressions that implement IEnumerable) and query operators can be parsed.
I started to implement IQueryable on SimplifiedPODLinqBuilder(as that seemed more logical than implementing IEnumberable) and thought I would be clever by doing this:
public class SimplifiedPODLinqBuilder : IQueryable
{
private IQueryable<POD> _pods;
...
public IEnumerator GetEnumerator()
{
return _pods.GetEnumerator();
}
public Expression Expression
{
get { return _pods.Expression; }
}
public Type ElementType
{
get { return _pods.ElementType; }
}
public IQueryProvider Provider
{
get { return _pods.Provider; }
}
}
only to get this exception (apparently Load is not being called and _pods is null):
System.NullReferenceException : Object reference not set to an instance of an object.
is there a way for me to refactor this code out that will parse properly into an expression that will go to SQL?
The part fam => _podLinqBuilder.Load(fam.PODs.AsQueryable() is never going to work, because the linq provider will try to parse this into SQL and for that it needs mapped members of Family after the =>, or maybe a mapped user-defined function but I don't know if Linq-to-Nhibernate supports that (I never really worked with it, because I still doubt if it is production-ready).
So, what can you do?
To be honest, I like the extension methods much better. You switched to a stateful approach, which doesn't mix well with the stateless paradigm of linq. So you may consider to retrace your steps.
Another option: the expression in .Any(pod => pod.Route.RouteID == route.RouteID)); could be paremeterized (.Any(podExpression), with
OnRoute(WicRoute route, Expression<Func<POD,bool>> podExpression)
(pseudocode).
Hope this makes any sense.
You need to separate methods you intend to call from expressions you intend to translate.
This is great, you want each of those methods to run. They return an instance that implements IQueryable<Family> and operate on that instance.
var families = new SimplifiedFamilyLinqBuilder()
.Load(session.Query<Family>())
.OnRoute(new WicRoute() {RouteID = 1})
.AsQueryable()
.ToList();
This is no good. you don't want Queryable.Where to get called, you want it to be an expression tree which can be translated to SQL. But PodLinqBuilder.Load is a node in that expression tree which can't be translated to SQL!
families = _families
.Where(fam => _podLinqBuilder.Load(fam.PODs.AsQueryable())
.OnRoute(route)
.AsQueryable()
.Any();
You can't call .Load inside the Where expression (it won't translate to sql).
You can't call .Load outside the Where expression (you don't have the fam parameter).
In the name of "separation of concerns", you are mixing query construction methods with query definition expressions. LINQ, by its Integrated nature, encourages you to attempt this thing which will not work.
Consider making expression construction methods instead of query construction methods.
public static Expression<Func<Pod, bool>> GetOnRouteExpr(WicRoute route)
{
int routeId = route.RouteID;
Expression<Func<Pod, bool>> result = pod => pod.Route.RouteID == route.RouteID;
return result;
}
called by:
Expression<Func<Pod, bool>> onRoute = GetOnRouteExpr(route);
families = _families.Where(fam => fam.PODs.Any(onRoute));
With this approach, the question is now - how do I fluidly hang my ornaments from the expression tree?
I am using Entity Framework 4.0 and trying to use the "Contains" function of one the object sets in my context object. to do so i coded a Comparer class:
public class RatingInfoComparer : IEqualityComparer<RatingInfo>
{
public bool Equals(RatingInfo x, RatingInfo y)
{
var a = new {x.PlugInID,x.RatingInfoUserIP};
var b = new {y.PlugInID,y.RatingInfoUserIP};
if(a.PlugInID == b.PlugInID && a.RatingInfoUserIP.Equals(b.RatingInfoUserIP))
return true;
else
return false;
}
public int GetHashCode(RatingInfo obj)
{
var a = new { obj.PlugInID, obj.RatingInfoUserIP };
if (Object.ReferenceEquals(obj, null))
return 0;
return a.GetHashCode();
}
}
when i try to use the comparer with this code:
public void SaveRatingInfo2(int plugInId, string userInfo)
{
RatingInfo ri = new RatingInfo()
{
PlugInID = plugInId,
RatingInfoUser = userInfo,
RatingInfoUserIP = "192.168.1.100"
};
//This is where i get the execption
if (!context.RatingInfoes.Contains<RatingInfo>(ri, new RatingInfoComparer()))
{
//my Entity Framework context object
context.RatingInfoes.AddObject(ri);
context.SaveChanges();
}
}
i get an execption:
"LINQ to Entities does not recognize the method 'Boolean Contains[RatingInfo](System.Linq.IQueryable1[OlafCMSLibrary.Models.RatingInfo], OlafCMSLibrary.Models.RatingInfo,
System.Collections.Generic.IEqualityComparer1[OlafCMSLibrary.Models.RatingInfo])' method, and his method cannot be translated into a store expression."
Since i am not proficient with linQ and Entity Framework i might be making a mistake with my use of the "var" either in the "GetHashCode" function or in general.
If my mistake is clear to you do tell me :) it does not stop my project! but it is essential for me to understand why a simple comparer doesnt work.
Thanks
Aaron
LINQ to Entities works by converting an expression tree into queries against an object model through the IQueryable interface. This means than you can only put things into the expression tree which LINQ to Entities understands.
It doesn't understand the Contains method you are using, so it throws the exception you see. Here is a list of methods which it understands.
Under the Set Methods section header, it lists Contains using an item as supported, but it lists Contains with an IEqualityComparer as not supported. This is presumably because it would have to be able to work out how to convert your IEqualityComparer into a query against the object model, which would be difficult. You might be able to do what you want using multiple Where clauses, see which ones are supported further up the document.
When using ria service for SL app, I can issue following async call to get a group of entity list.
LoadOperation<Person> ch =
this.AMSContext.Load(this.AMSContext.GetPersonQuery().Where(a => a.PersonID == this.performer.PersonID));
But I want to get some calculation, for example, sum(Commission), sum(Salary), the result is not entity, just a scalar value. How can I do this?
You could use methods that return any values with WCF methods.
On the server side you will have something like this
[EnableClientAccess()]
public class AMSContext : DomainService
{
public float CalucalteCommissionSum()
{
// make your linq query and return the result here
}
}
And you can access it from the client like this :
this.AMSContext.CalucalteCommissionSum(x => context_CalucalteCommissionSumCompleted(x), null);
void context_CalucalteCommissionSumCompleted(System.Windows.Ria.InvokeOperation<float> op)
{
// you will have the value in op.Value
}
Check this question for more details.