在這個Outlook 2007應用程序中，Explorers.NewExplorer事件怎麼沒有被觸發？

Question

下面是一些示例代碼：

private Outlook.Application applicationObject; 
    public void OnConnection(object application, Extensibility.ext_ConnectMode connectMode, object addInInst, ref System.Array custom) 
    { 
     MessageBox.Show("on connection"); 
     applicationObject = (Outlook.Application)application; 
     applicationObject.Explorers.NewExplorer += new Microsoft.Office.Interop.Outlook.ExplorersEvents_NewExplorerEventHandler(Explorers_NewExplorer); 
    } 

    void Explorers_NewExplorer(Microsoft.Office.Interop.Outlook.Explorer Explorer) 
    { 
     MessageBox.Show("new explorer"); 
    } 

「新資源管理器」的消息從來沒有出現在屏幕上，因爲NewExplorer事件永遠不會觸發，即使是在我點擊「在新窗口打開」。

什麼可能是錯的？

Answer 1

您訂閱NewExplorer事件的Explorers實例可能正在進行垃圾回收。爲防止這種情況發生，請通過實例變量保留對其的引用：

private Outlook.Application applicationObject; 
private Outlook.Explorers explorers; 

public void OnConnection(object application, Extensibility.ext_ConnectMode connectMode, object addInInst, ref System.Array custom) 
{ 
    MessageBox.Show("on connection"); 
    applicationObject = (Outlook.Application)application; 
    explorers = applicationObject.Explorers; 
    explorers.NewExplorer += new Microsoft.Office.Interop.Outlook.ExplorersEvents_NewExplorerEventHandler(Explorers_NewExplorer); 
}