c# – BindingList不更新绑定的ListBox

线程和“观察者”模式(例如winforms上的数据绑定)很少是好朋友.您可以尝试替换BindingList< T>与ThreadedBindingList< T>的使用我在previous answer上使用的代码 – 但这种线程和UI的组合并不是winforms数据绑定的故意用例.

列表框本身应该支持通过列表通知事件(IBindingList / IBindingListView)进行绑定,只要它们到达形成正确的线程即可. ThreadedBindingList< T>尝试通过代表您的线程切换来解决此问题.请注意,要使其工作,您必须创建ThreadedBindingList< T>来自UI线程,在它具有同步上下文之后,即在它开始显示表单之后.

为了说明列表框确实尊重列表更改通知(处理单个线程时)：

using System;
using System.ComponentModel;
using System.Windows.Forms;
class Foo
{
    public int Value { get; set; }
    public Foo(int value) { Value = value; }
    public override string ToString() { return Value.ToString(); }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        using(var form = new Form())
        using (var lst = new ListBox())
        using (var timer = new Timer())
        {
            var data = new BindingList<Foo>();
            form.Controls.Add(lst);
            lst.DataSource = data;
            timer.Interval = 1000;
            int i = 0;
            timer.Tick += delegate
            {
                data.Add(new Foo(i++));
            };
            lst.Dock = DockStyle.Fill;
            form.Shown += delegate
            {
                timer.Start();
            };
            Application.Run(form);
        }
    }
}

现在添加了线程/ ThreadedBindingList< T> (它不适用于常规BindingList< T>)：

using System;
using System.ComponentModel;
using System.Threading;
using System.Windows.Forms;
class Foo
{
    public int Value { get; set; }
    public Foo(int value) { Value = value; }
    public override string ToString() { return Value.ToString(); }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        using(var form = new Form())
        using (var lst = new ListBox())
        {
            form.Controls.Add(lst);            
            lst.Dock = DockStyle.Fill;
            form.Shown += delegate
            {
                BindingList<Foo> data = new ThreadedBindingList<Foo>();
                lst.DataSource = data;
                ThreadPool.QueueUserWorkItem(delegate
                {
                    int i = 0;
                    while (true)
                    {
                        data.Add(new Foo(i++));
                        Thread.Sleep(1000);
                    }
                });
            };
            Application.Run(form);
        }
    }
}
public class ThreadedBindingList<T> : BindingList<T>
{
    private readonly SynchronizationContext ctx;
    public ThreadedBindingList()
    {
        ctx = SynchronizationContext.Current;
    }
    protected override void OnAddingNew(AddingNewEventArgs e)
    {
        SynchronizationContext ctx = SynchronizationContext.Current;
        if (ctx == null)
        {
            BaseAddingNew(e);
        }
        else
        {
            ctx.Send(delegate
            {
                BaseAddingNew(e);
            },null);
        }
    }
    void BaseAddingNew(AddingNewEventArgs e)
    {
        base.OnAddingNew(e);
    }
    protected override void OnListChanged(ListChangedEventArgs e)
    {
        if (ctx == null)
        {
            BaseListChanged(e);
        }
        else
        {
            ctx.Send(delegate
            {
                BaseListChanged(e);
            },null);
        }
    }
    void BaseListChanged(ListChangedEventArgs e)
    {
        base.OnListChanged(e);
    }
}