Question

我正在尝试创建一个可以其他形式访问的委托事件。但主要形式似乎没有能够看到我的代表。它表示委托名称此时无效。模态形式

public partial class GameOverDialog : Window
{
   public delegate void ExitChosenEvent();
   public delegate void RestartChosenEvent();

   public GameOverDialog()
   {
      InitializeComponent();
   }

   private void closeAppButton_Click(object sender, RoutedEventArgs e)
   {
      ExitChosenEvent exitChosen = Close;
      exitChosen();
      Close();
   }

   private void newGameButton_Click(object sender, RoutedEventArgs e)
   {
      RestartChosenEvent restart = Close;
      restart();
      Close();
   }
}

主要形式：

private void ShowGameOver(string text)
{
   var dialog = new GameOverDialog { tb1 = { Text = text } };
   dialog.RestartChosenEvent += StartNewGame();
   dialog.Show();
}

private void StartNewGame()
{
   InitializeComponent();
   InitializeGame();
}

@Fuex的帮助后 *

private void ShowGameOver(string text)
{
   var dialog = new GameOverDialog { tb1 = { Text = text } };
   dialog.RestartEvent += StartNewGame;
   dialog.ExitEvent += Close;
   dialog.Show();
}

Answer 1

它不起作用，因为delegate void RestartChosenEvent()声明了允许封装方法的引用类型。因此，通过使用它+= StartNewGame会出错。正确的代码是：

public partial class GameOverDialog : Window
{
    delegate void myDelegate();

    public myDelegate RestartChosenEvent;
    public myDelegate ExitChosenEvent;

    public GameOverDialog()
    {
        InitializeComponent();
    }

    private void closeAppButton_Click(object sender, RoutedEventArgs e)
    {
        ExitChosenEvent();
        this.Close();
    }

    private void newGameButton_Click(object sender, RoutedEventArgs e)
    {
        RestartChosenEvent();
        this.Close();
    }
}

然后在您的主表单中，您必须使用StartNewGame，这是要传递的方法的指针，而不是StartNewGame()：

private void ShowGameOver(string text)
{
   var dialog = new GameOverDialog { tb1 = { Text = text } };
   dialog.RestartChosenEvent += StartNewGame;
   dialog.Show();
}

Answer 2

'委托名称此时无效'错误也可能在您定义委托而不使用 new 关键字时发生。例如：

// In asp.net the below would typically appear in a parent page (aspx.cs page) that 
// consumes a delegate event from a usercontrol:
    protected override void OnInit(EventArgs e) 
    { 
        Client1.EditClientEvent += Forms_Client.EditClientDelegate(Client1_EditClientEvent); 
        //NOTE: the above line causes 'delegate name is not valid at this point' error because of the lack of the 'new' keyword.
        Client1.EditClientEvent += new Forms_Client.EditClientDelegate(Client1_EditClientEvent); 
        //NOTE: the above line is the correct syntax (no delegate errors appear)
    }

要将其置于上下文中，您可以在下面看到委托的定义。在asp.net中，如果您要定义需要从其父页面（托管控件的页面）获取值的usercontrol，那么您将在usercontrol中定义您的委托，如下所示：

//this is the usercontrol (ascx.cs page):
    public delegate void EditClientDelegate(string num); 
    public event EditClientDelegate EditClientEvent; 
    //call the delegate somewhere in your usercontrol:
    protected void Page_Load(object sender, System.EventArgs e)
    {
        if (EditClientEvent != null) { 
            EditClientEvent("I am raised"); 
        }
    }

创建委托事件

2 个答案: