事件未调用 C#

Question

我目前正在制作一个 NFC 库，当卡片被成功读取时，我需要在其中引发一个事件。

在我的 MainProject 中，我这样调用库：

reader = new NfcReader();
    if (reader.Initialize())
    {
        reader.UidReceived += (s, args) => 
            DisplayText(String.Format("UID received: {0}", args.Uid));
    }

我的图书馆：

public class NfcReader
{
    private SCardMonitor monitor;
    public event EventHandler<NfcReaderEventArgs> UidReceived;

    public bool Initialize()
    {
        // When a card is inserted, an event is raised
        // then I want to read the Uid of the card 
        monitor = new SCardMonitor(new SCardContext(), SCardScope.System);
        monitor.CardInserted += (s,a) => GetUid(a.ReaderName);
        return true;
    }

    private void GetUid(string readerName)
    {
        string uid = MyUidGetter(readerName);
        OnUidReceived(uid);
    }

    private void OnUidReceived(string uid)
    {
        var handler = UidReceived;
        if (handler == null)
        {
            handler(this, new NfcReaderEventArgs(uid));
        }
    }
}

调试器逐步执行 handler(this, new NfcReaderEventArgs(uid));，但未调用 DisplayText 方法。有什么想法吗？

Answer 1

我猜你检查处理程序是否为空是一个错字？ ;)

也许您的 Initialize return 错误。调试器会逐步执行，因为它不会调用任何东西。这是由 if.

确定的

我建议您改用 handler != null 并确保 Initialize returns 为真。

事件未调用 C#

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