使用线程从外部 dll 传回数据

Question

我有一个通用的通信库，我已经编写了它来通过 TCP/IP 与我们的硬件进行通信

公共库允许客户端应用程序和我们的工程师工具共享公共代码。 公共库运行需要将数据返回到表单的线程。

我有一些工作代码，但我觉得必须有更简单的方法来做到这一点。

这是我所拥有的简化版本...

namespace EngineerTool
{

    public delegate void DelegateSearchFinished();

    public partial class MainForm : Form
    {
        public DelegateSearchFinished d_SearchFinished;
        Discover discovery;

        public MainForm()
        {
            InitializeComponent();
            discovery = new Discover(this.FinishedSearchInvoke);
            d_SearchFinished = new DelegateSearchFinished(this.FinishedSearch);
            discovery.Start();
        }

        public void FinishedSearchInvoke()
        {
            this.Invoke(this.d_SearchFinished, new Object[] {});
        }

        public void FinishedSearch()
        {
            // Search has finished here!
        }
    }
}

namespace DiscoveryTool
{
    public delegate void DelegateSearchFinished();

    public class Discover
    {
        DelegateSearchFinished _callFinished;

        public Discover(DelegateSearchFinished callFinished)
        {
            _callFinished = callFinished;
        }

        public void Start()
        {
            // starts thread and stuff
        }

        public void ThreadWorker()
        {



            _callFinished();
        }

    }
}

Answer 1

如果在 Discover 类上创建一个事件，Form 订阅该事件，而不是传递委托。

Answer 2

看看BackgroundWorker类：​​

BackgroundWorker Component Overview

Answer 3

假设您正在执行将产生List<Customer> 对象的搜索。然后，一种相当直接且简单的方法是在搜索完成时引发一个事件，使用携带结果的特殊 EventArgs 类：

public class CustomerSearchEventArgs : EventArgs
{
    public List<Customer> Customers { get; private set; }
    public CustomerSearchEventArgs(List<Customer> customers)
    {
        Customers = customers;
    }
}

...在搜索类中：

// the parameter is there to conform to the signature of the WaitDelegate
// used when invoking the method using the ThreadPool
public void Search(object state)
{    
    List<Customer> result = new List<Customer>();
    // perform the search, populate the result list
    // call a method to raise the event
    OnSearchFinished(new CustomerSearchEventArgs(result));
}

protected void OnSearchFinished(CustomerSearchEventArgs e)
{
    EventHandler<CustomerSearchEventArgs> searchFinished = this.SearchFinished;
    if (searchFinished != null)
    {
        searchFinished(this, e);
    }
}

...形式为：

private delegate void CustomerListHandler(List<Customer> customers);

private void StartSearch()
{
    CustomerSearch search = new CustomerSearch();
    search.SearchFinished += new EventHandler<CustomerSearchEventArgs>(Search_SearchFinished);
    ThreadPool.QueueUserWorkItem(search.Search);
}
private void Search_SearchFinished(object sender, CustomerSearchEventArgs e)
{
    SearchFinished(e.Customers);
}

private void SearchFinished(List<Customer> list)
{
    if (this.InvokeRequired)
    {
        // the method is NOT executing on the UI thread; we
        // need to invoke it on the right thread
        this.Invoke(new CustomerListHandler(SearchFinished), list);
    }
    else
    {
        lstCustomers.Items.Clear();
        lstCustomers.DisplayMember = "Name";
        lstCustomers.Items.AddRange(list.ToArray());
    }
}