本文介紹了如何將 TransactionScope 與 MySql 和實體框架一起使用?(獲取多個同時連接...目前不支持錯誤)的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我有一個新的 .NET 4.0 控制臺應用程序，它使用:
I have a new .NET 4.0 console application that uses:
- MySql 6.4.4.0
- 實體框架 4.2(代碼優先)
- Visual Studio 2010
到目前為止，這是有效的.我可以很好地添加和讀取數據庫.
So far this works. I can add and read from the database fine.
現在，當我添加 TransactionScope 時，如下例所示:
Now, when I add TransactionScope, as in the following example:
public static void TestInsert()
{
using (TransactionScope scope = new TransactionScope())
{
using (var context = new MyDbContext())
{
// Create a test user
DateTime dt = DateTime.Now;
var user1 = new User { UserID = 1, UserName = "test" };
context.Users.Add(user1); <-- exception occurs here
context.SaveChanges();
}
}
}
當我運行這個時，我收到錯誤:
When I run this, I get the error:
當前不支持多個同時連接或在同一事務內具有不同連接字符串的連接.
似乎即使是最新版本的 MySql 也不喜歡 TransactionScope 與 EntityFramework 一起工作.
It seems that even the latest version of MySql does not like TransactionScope working with EntityFramework.
我希望能夠使用事務，尤其是在測試項目中，以便我可以回滾任何更改.
I want to be able to use transactions, especially in test projects so that I can roll back any changes.
知道如何解決或解決此問題嗎?
Any idea how I can fix this or work around it?
完整的錯誤信息
System.Data.DataException was unhandled
Message=An exception occurred while initializing the database. See the InnerException for details.
Source=EntityFramework
StackTrace:
at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()
at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c)
at System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()
at System.Data.Entity.Internal.InternalContext.Initialize()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action action, EntityState newState, Object entity, String methodName)
at System.Data.Entity.Internal.Linq.InternalSet`1.Add(Object entity)
at System.Data.Entity.DbSet`1.Add(TEntity entity)
InnerException: System.Data.EntityException
Message=The underlying provider failed on Open.
Source=System.Data.Entity
StackTrace:
at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
at System.Data.EntityClient.EntityConnection.Open()
at System.Data.Objects.ObjectContext.EnsureConnection()
at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
at System.Data.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__1[TResult](IEnumerable`1 sequence)
at System.Data.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
at System.Data.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[S](Expression expression)
at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
at System.Data.Entity.Internal.InternalContext.QueryForModelHash()
at System.Data.Entity.Internal.InternalContext.CompatibleWithModel(Boolean throwIfNoMetadata)
at System.Data.Entity.Database.CompatibleWithModel(Boolean throwIfNoMetadata)
at System.Data.Entity.CreateDatabaseIfNotExists`1.InitializeDatabase(TContext context)
at System.Data.Entity.Internal.InternalContext.<>c__DisplayClass5.<PerformDatabaseInitialization>b__3()
at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
InnerException: System.NotSupportedException
Message=Multiple simultaneous connections or connections with different connection strings inside the same transaction are not currently supported.
Source=MySql.Data
StackTrace:
at MySql.Data.MySqlClient.MySqlConnection.Open()
at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
InnerException:
一些類(不復雜):
[Table("User")]
public class User
{
public User()
{
}
// Primary key
[Key]
public int UserID { get; set; }
public string UserName { get; set; }
}
public class MyDbContext : DbContext
{
public MyDbContext() : base("DbContext")
{
}
public DbSet<User> Users { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// Tell Code First to ignore PluralizingTableName convention
// If you keep this convention then the generated tables will have pluralized names.
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
}
App.config:
<?xml version="1.0"?>
<configuration>
<connectionStrings>
<clear/>
<add name="DbContext" connectionString="Server=localhost; Database=****; Uid=****; Pwd=****;" providerName="MySql.Data.MySqlClient"/>
</connectionStrings>
<system.data>
<DbProviderFactories>
<remove invariant="MySql.Data.MySqlClient"/>
<add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data"/>
</DbProviderFactories>
</system.data>
</configuration>
提前致謝，
丹
推薦答案
試試這個，創建上下文后創建事務.
Try this, Create transaction after creating context.
public static void TestInsert()
{
using (var context = new MyDbContext())
{
using (TransactionScope scope = new TransactionScope())
{
// Create a test user
DateTime dt = DateTime.Now;
var user1 = new User { UserID = 1, UserName = "test" };
context.Users.Add(user1);
context.SaveChanges();
scope.Complete();
}
}
}
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