mani mani - 2 months ago 16
C# Question

Repository - open DataReader associated with this Command which must be closed first

I have a method for starting a game written in MVC with Entity Framework and it's been over the Repository and Unit of works:

public Team StartTeam(Message message, out string result)
{
try
{
var player = GetPlayer(message);
if (player.StatusId == (int)Status.Playing)
{
result = Mesages.CantStartGameDuringAnotherGame;
return null;
}
var team = Uow.TeamContext.FindBy(q => q.Name == message.Text).FirstOrDefault();
if (team == null)
{
result = Mesages.UnexpectedError;
return null;
}
var members = Uow.MembershipContext.FindBy(q => q.TeamId == team.Id);
var players = new List<Player>();
foreach (var member in members.Where(q => q.PlayerId != player.Id))
{
var pl = Uow.PlayerContext.GetSingle(member.PlayerId);
if (player.StatusId == (int)Status.Active)
players.Add(pl);
}
players.Add(player);
player.StatusId = (int)Status.Active;
if (players.Count < 2)
{
result = Mesages.NotEnoughPlayers;
return null;
}
var race = new Race()
{
TeamId = team.Id,
PlayDate = DateTime.Now
};
race = Uow.RaceContext.Add(race);
Uow.Save();
team.CurrentRaceId = race.Id;
foreach (var playr in players)
{
playr.StatusId =
members.First(q => q.PlayerId == playr.Id).StatusId
= (int)Status.Playing;
playr.CurrentTeamId = team.Id;
}
result = Mesages.TeamStartedSuccessfuly;
player.StatusId = (int)Status.Playing;
return team;
}
catch (Exception ex)
{
SaveException(ex);
return null;
}
}


Every things seems to be ok and I can run it in my local but when I publish it I gave this error:

There is already an open DataReader associated with this Command which must be closed first.


This is complete stack trace:

System.Data.Entity.Core.EntityCommandExecutionException: An error occurred while executing the command definition. See the inner exception for details. ---> System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first.
at System.Data.SqlClient.SqlInternalConnectionTds.ValidateConnectionForExecute(SqlCommand command)
at System.Data.SqlClient.SqlConnection.ValidateConnectionForExecute(String method, SqlCommand command)
at System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
at System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<Reader>b__c(DbCommand t, DbCommandInterceptionContext`1 c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.Reader(DbCommand command, DbCommandInterceptionContext interceptionContext)
at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
--- End of inner exception stack trace ---
at System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)
at System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlan.Execute[TResultType](ObjectContext context, ObjectParameterCollection parameterValues)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass7.<GetResults>b__6()
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClass7.<GetResults>b__5()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0()
at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__1[TResult](IEnumerable`1 sequence)
at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source, Expression`1 predicate)
at EsmFamilWebHoook.Models.PlayerRepository.GetSingle(Int32 playerId)
at EsmFamilWebHoook.DatabaseService.StartTeam(Message message, String& result)


What happened?
I saw this post but not helped me!

Answer

Might be that your query:

var pl = Uow.PlayerContext.GetSingle(member.PlayerId);

is placed inside foreach which iterates over result of another query (but this query might still be active - may be it read just first batch of rows or it doing some lazy loading):

foreach (var member in Uow.MembershipContext.FindBy(q => q.TeamId == team.Id).Where(q => q.PlayerId != player.Id))

Try to force result of first query to be fully loaded into memory first using .ToArray() for example:

foreach (var member in Uow.MembershipContext.FindBy(q => q.TeamId == team.Id).Where(q => q.PlayerId != player.Id).ToArray())

Generally you can have 1 query active at time.