事件處理空

Question

在MainWindow構造，我註冊一個事件處理程序：

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"); 
     } 
    } 
} 

但在PageViewDocText，NewPageIRPRO是空

我在做什麼錯？我想撥打MainWindow.ViewIPRO。

此事件處理火災和註冊下面pageViewDocText.NewPageIRPRO行+ =

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

Answer 1

看起來你在呼喚從另一個類（未上市）的事件，是有缺失的委託。

試試這個代碼：

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"); 
     } 
    } 
}