c# - 事件处理程序为空

Question

在 MainWindow 构造函数中，我正在注册一个事件处理程序:

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public MainWindow()
    {
        InitializeComponent();
        pageViewDocText = new PageViewDocText();
        framePageDocFieldDetail.Content = pageViewDocText;
        pageViewDocText.NewPageIRPRO += new GabeLib.SearchCls.DocEventHandler(ViewIPRO);
    }

    protected void ViewIPRO(string IRPOlink) // ...
}

public partial class PageViewDocText : Page, INotifyPropertyChanged
{
    public event GabeLib.SearchCls.DocEventHandler NewPageIRPRO;

    private void btn_PageBreakNext(object sender, RoutedEventArgs e)
    {
        // this fires but NewPageIRPRO is null
        if (NewPageIRPRO != null)
        {
            NewPageIRPRO("dummylink");
        }
    }
}

但是在PageViewDocText中，NewPageIRPRO为空

我做错了什么？
从 PageViewDocText，我想调用 MainWindow.ViewIPRO。

此事件处理程序将触发并在 pageViewDocText.NewPageIRPRO += 下面的行中注册

App.StaticGabeLib.Search.NewDocIRPRO += new GabeLib.SearchCls.DocEventHandler(ViewIPRO);

Answer 1

看起来您正在调用另一个类(未列出)的事件并且缺少委托(delegate)。

试试这段代码:

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public MainWindow()
    {
        InitializeComponent();
        pageViewDocText = new PageViewDocText();
        framePageDocFieldDetail.Content = pageViewDocText;
        pageViewDocText.PageBreakNext += new PageBreakNext(ViewIPRO);
    }

    protected void ViewIPRO(string IRPOlink) // ...
}

public partial class PageViewDocText : Page, INotifyPropertyChanged
{
    public delegate void PageBreakNext(string IRPOlink);
    public event PageBreakNext PageBreak;

    private void btn_PageBreakNext(object sender, RoutedEventArgs e)
    {
        // this fires but NewPageIRPRO is null
        if (PageBreak != null)
        {
            PageBreak("dummylink");
        }
    }
}