Question

我想让我的列表框在我的帖子结束时清除它。我有问题调用它，并希望有人会告诉我如何。

 public delegate void ClearDelegate(ListBox lb);


        public void ItemClear(ListBox lb)
        {
            if (lb.InvokeRequired)
            {
                lb.Invoke(new ClearDelegate(ItemClear), new Object[] { lb });
            }

            listBox1.Items.Clear();

        }

Answer 1

使用它自己的主题非常简单的例子（注意仅用于显示，更好的是这里可能是BackgroundWorker！）：

private Thread _Thread;

public Form1()
{
    InitializeComponent();
    _Thread = new Thread(OnThreadStart);
}

private void OnButton1Click(object sender, EventArgs e)
{
    var state = _Thread.ThreadState;

    switch (state)
    {
        case ThreadState.Unstarted:
            _Thread.Start(listBox1);
            break;
        case ThreadState.WaitSleepJoin:
        case ThreadState.Running:
            _Thread.Suspend();
            break;
        case ThreadState.Suspended:
            _Thread.Resume();
            break;
    }
}

private static void OnThreadStart(object obj)
{
    var listBox = (ListBox)obj;
    var someItems = Enumerable.Range(1, 10).Select(index => "My Item " + index).ToArray();

    foreach (var item in someItems)
    {
        listBox.Invoke(new Action(() => listBox.Items.Add(item)));
        Thread.Sleep(1000);
    }

    listBox.Invoke(new Action(() => listBox.Items.Clear()));
}

Answer 2

根据MSDN documentation 应该将listBox1.Items.Clear();语句放入else语句中。

另一件事是你可以使用不阻塞线程的异步方法BeginInvoke来等待方法完成。

Answer 3

只能通过UI线程而不是工作线程访问列表框。

    var sync = SynchronizatoinContext.Current;

    sync.Post(delegate {
     // Perform UI related changes here
}, null) //as the worker thread cannot access the UI thread resources

在线程中调用Listbox

3 个答案: