IAsyncResult 接口的正确实现是什么？

发布于 2024-07-21 01:26:06 字数 2456 浏览 10 评论 0原文

我正在考虑为我创建的类添加一些灵活性，该类建立与远程主机的连接，然后执行信息交换（握手）。当前的实现提供了一个 Connect 函数，该函数建立连接，然后阻止等待 ManualResetEvent，直到双方完成握手。

下面是调用我的类的示例：

// create a new client instance
ClientClass cc = new ClientClass("address of host");
bool success = cc.Connect();  // will block here until the
                              //  handshake is complete
if(success)
{

}

..这是该类内部功能的过度简化的高级视图：

class ClientClass
{
    string _hostAddress;
    ManualResetEvent _hanshakeCompleted;
    bool _connectionSuccess;

    public ClientClass(string hostAddress)
    {
        _hostAddress = hostAddress;            
    }

    public bool Connect()
    {
        _hanshakeCompleted = new ManualResetEvent(false);            
        _connectionSuccess = false;

        // start an asynchronous operation to connect
        //  ...
        //  ...

        // then wait here for the connection and
        //  then handshake to complete
        _hanshakeCompleted.WaitOne();

        // the _connectionStatus will be TRUE only if the
        //  connection and handshake were successful
        return _connectionSuccess;
    }

    // ... other internal private methods here
    // which handle the handshaking and which call
    // HandshakeComplete at the end

    private void HandshakeComplete()
    {
        _connectionSuccess = true;
        _hanshakeCompleted.Set();
    }
}

我正在考虑实现此类的 .NET 经典异步模式。为此，我将提供 BeginConnect 和 EndConnect 函数，并允许该类的用户编写如下代码：

ClientClass cc = new ClientClass("address of host");
cc.BeginConnect(new AsyncCallback(ConnectCompleted), cc);
// continue without blocking to this line

// ..

void ConnectCompleted(IAsyncResult ar)
{
    ClientClass cc = ar.AyncState as ClientClass;
    try{
        bool success = cc.EndConnect(ar);
        if(success)
        {
             // do more stuff with the 
             //  connected Client Class object
        }
    }
    catch{
    }
}

为了能够提供此 API，我需要创建一个实现 IAsyncResult 接口的类，该接口由BeginConnect函数，并分别传递到EndConnect函数中。

现在，我的问题是：在类中实现 IAsyncResult 接口的正确方法是什么？

一个明显的解决方案是创建一个具有 Connect 函数匹配签名的委托，然后异步调用该委托使用 BeginInvoke - EndInvoke 但这不是我正在寻找的（它不是很有效）。

我对如何做到这一点有一个粗略的想法，但是在查看了 .NET 框架内部他们如何在某些地方实现此模式之后，我觉得明智的做法是询问并看看是否有人成功地做到了这一点，如果是，那么有什么需要特别注意的问题领域。

谢谢！

原文

I'm looking into adding some flexibility to a class that I've created which establishes a connection to a remote host and then performs an exchange of information (a handshake). The current implementation provides a Connect function which establishes the connection and then blocks waiting on a ManualResetEvent untill the two parties have completed the handshake.

Here's an example of what calling my class looks like:

// create a new client instance
ClientClass cc = new ClientClass("address of host");
bool success = cc.Connect();  // will block here until the
                              //  handshake is complete
if(success)
{

}

..and here's an oversimplified high-level view of what the class does internally:

class ClientClass
{
    string _hostAddress;
    ManualResetEvent _hanshakeCompleted;
    bool _connectionSuccess;

    public ClientClass(string hostAddress)
    {
        _hostAddress = hostAddress;            
    }

    public bool Connect()
    {
        _hanshakeCompleted = new ManualResetEvent(false);            
        _connectionSuccess = false;

        // start an asynchronous operation to connect
        //  ...
        //  ...

        // then wait here for the connection and
        //  then handshake to complete
        _hanshakeCompleted.WaitOne();

        // the _connectionStatus will be TRUE only if the
        //  connection and handshake were successful
        return _connectionSuccess;
    }

    // ... other internal private methods here
    // which handle the handshaking and which call
    // HandshakeComplete at the end

    private void HandshakeComplete()
    {
        _connectionSuccess = true;
        _hanshakeCompleted.Set();
    }
}

I'm looking into implementing the .NET Classic Async Pattern for this class. In doing so, I would provide BeginConnect and EndConnect functions, and allow the users of the class to write code like this:

ClientClass cc = new ClientClass("address of host");
cc.BeginConnect(new AsyncCallback(ConnectCompleted), cc);
// continue without blocking to this line

// ..

void ConnectCompleted(IAsyncResult ar)
{
    ClientClass cc = ar.AyncState as ClientClass;
    try{
        bool success = cc.EndConnect(ar);
        if(success)
        {
             // do more stuff with the 
             //  connected Client Class object
        }
    }
    catch{
    }
}

In order to be able to provide this API I need to create a class that implements the IAsyncResult interface to be returned by the BeginConnect function, and to be passed into the EndConnect function respectively.

Now, my question is: What is a proper way to implement the IAsyncResult interface in a class?

One obvious solution would be to create a delegate with a matching signature for the Connect function and then invoke that delegate asynchronously using BeginInvoke - EndInvoke but that is not what I'm looking for (it's not very efficient).

I have a rough idea of how I could do it but after peeking inside the .NET framework at how they implement this pattern in some places I felt it would be wise to ask and see if anybody has done this successfully and if so what are the problem areas to pay special attention to.

Thanks!

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