EntityConnection 只能用封闭的 DbConnection 来构造

发布于 2024-12-01 07:52:12 字数 1322 浏览 2 评论 0原文

“EntityConnection 只能用封闭的 DbConnection 来构造” 这是我在尝试构建提供开放连接的实体连接时遇到的问题。有一个打开的事务范围，我不想打开一个新连接，否则该事务将被提升为 dtc 事务，因为我的理解是，如果我在多个实体连接上使用单个 SqlConnection，我不需要 DTC。

所以，我的代码大约是这样的。

提前致谢...

    using (TransactionScope transactionScope = new TransactionScope())
{

    using (SqlConnection dwConn = GetDWConnection(user)) 
    {
        dwConn.Open();
        // I need to do some SQlConnection specific actions first

        //EntityConnection specific actions next
        Func1(dwConn);
        Func2(dwConn); //similar to Func1()
        Func3(dwConn); //Similar to Func1()

    }

}
    Func1(SqlConnection dwConn)
    {
        using (EntityConnection conn = GetSQLEntityConnection(sqlConnection))
        {
            ObjectContext objectContext = (ObjectContext)Activator.CreateInstance(objectContextType, new object[] { conn });
            //few actions
        }
    }
    private EntityConnection GetSQLEntityConnection(SqlConnection sqlConnection)
        {
        //few steps
            EntityConnection entityConnection = new EntityConnection(entityConnectionStringBuilder.ToString());

            EntityConnection sqlEntityConnection = new EntityConnection(entityConnection.GetMetadataWorkspace(),sqlConnection);
            return sqlEntityConnection;
        }

原文

"EntityConnection can only be constructed with a closed DbConnection"
This is the problem I get when a try to construct an entityconnection providing an open connection.
There is a transactionscope open and I don't want to open a new connection or the transaction would be promoted to a dtc transaction as my understanding is that if I use a single SqlConnection over the multiple entityConnections, I don't need DTC.

So, my code is approximately like this.

Thanks in advance...

    using (TransactionScope transactionScope = new TransactionScope())
{

    using (SqlConnection dwConn = GetDWConnection(user)) 
    {
        dwConn.Open();
        // I need to do some SQlConnection specific actions first

        //EntityConnection specific actions next
        Func1(dwConn);
        Func2(dwConn); //similar to Func1()
        Func3(dwConn); //Similar to Func1()

    }

}
    Func1(SqlConnection dwConn)
    {
        using (EntityConnection conn = GetSQLEntityConnection(sqlConnection))
        {
            ObjectContext objectContext = (ObjectContext)Activator.CreateInstance(objectContextType, new object[] { conn });
            //few actions
        }
    }
    private EntityConnection GetSQLEntityConnection(SqlConnection sqlConnection)
        {
        //few steps
            EntityConnection entityConnection = new EntityConnection(entityConnectionStringBuilder.ToString());

            EntityConnection sqlEntityConnection = new EntityConnection(entityConnection.GetMetadataWorkspace(),sqlConnection);
            return sqlEntityConnection;
        }

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

ゃ人海孤独症 2024-12-08 07:52:12

雅库布是完全正确的。您既不能创建 DbContext 也不能创建 EntityConnection 并将打开的 DbConnection 传递给它们。

根据 Diego B Vega 的帖子此问题在 EF 6 发布之前不会得到修复 (这里你可以投票）

解决方法是在之前打开已经初始化的EntityConnection任何涉及它的操作。

给定ObjectContext，您可以像这样打开EntityConnection：

((EntityConnection)objectContext.Connection).Open();

在DbContext的情况下，EntityConnection可从底层获得对象上下文。代码可能是这样的：

class MyDbContext : DbContext
{
    public MyDbContext (DbConnection connection) 
                  : base (connection, contextOwnsConnection: true)
    {
        ((IObjectContextAdapter)this).ObjectContext.Connection.Open();
    }

    // …
}

class Program
{
    public static void Main()
    {
        var connection = new SqlConnection(CONNECTION_STRING);
        using (var database = new MyDbContext(connection))
        {
            Assert.IsTrue(connection.State == ConnectionState.Open);
        }
        Assert.IsTrue(connection.State == ConnectionState.Closed);
    }
}

Jakub is completely right. You can create neither DbContext nor EntityConnection with opened DbConnection passed to them.

According to Diego B Vega’s post this issue will not be fixed until EF 6 release (here you can vote for it)

The workaround is to open already initialized EntityConnection before any operations involving it.

Given ObjectContext you can open EntityConnection like this:

((EntityConnection)objectContext.Connection).Open();

In case of DbContext the EntityConnection is available from underlying ObjectContext. The code might be like this:

class MyDbContext : DbContext
{
    public MyDbContext (DbConnection connection) 
                  : base (connection, contextOwnsConnection: true)
    {
        ((IObjectContextAdapter)this).ObjectContext.Connection.Open();
    }

    // …
}

class Program
{
    public static void Main()
    {
        var connection = new SqlConnection(CONNECTION_STRING);
        using (var database = new MyDbContext(connection))
        {
            Assert.IsTrue(connection.State == ConnectionState.Open);
        }
        Assert.IsTrue(connection.State == ConnectionState.Closed);
    }
}

回复收藏 0 原文