wpf - 调用 RoutedEvent 时出现 ArgumentNullException

Question

以下代码产生 ArgumentNullException：

Public Custom Event PlayerDetailRequested As RoutedPropertyChangedEventHandler(Of Player)

    AddHandler(ByVal value As RoutedPropertyChangedEventHandler(Of Player))
        Me.AddHandler(PlayerDetailRequestedEvent, value)
    End AddHandler

    RemoveHandler(ByVal value As RoutedPropertyChangedEventHandler(Of Player))
        Me.RemoveHandler(PlayerDetailRequestedEvent, value)
    End RemoveHandler

    RaiseEvent(ByVal sender As Object, ByVal e As RoutedPropertyChangedEventArgs(Of Player))
        Me.RaiseEvent(e)
    End RaiseEvent
End Event

Public Shared ReadOnly PlayerDetailRequestedEvent As RoutedEvent = _
                  EventManager.RegisterRoutedEvent("PlayerDetailRequested", _
                  RoutingStrategy.Bubble, _
                  GetType(RoutedPropertyChangedEventHandler(Of Player)), GetType(PlayersManagementControl))



  Private Sub Hyperlink_Click(sender As Object, e As RoutedEventArgs)
        RaiseEvent PlayerDetailRequested(Me, New RoutedPropertyChangedEventArgs(Of Player)(SelectedPlayer, SelectedPlayer))
    End Sub

调用时抛出异常Me.RaiseEvent(e)

在 VB 中很难找到工作示例，而 C sharp 的事件处理不同。请帮助我保持理智！

Answer 1

该问题在Exception:中进行了解释Value cannot be null. Parameter name: routedEvent。RoutedEvent是 a 的属性RoutedEventArgs。您必须提供RoutedEvent您正在提出的实例，在您的情况下是PlayerDetailRequestedEvent. 试试这段代码：

    Private Sub Button_Click_1(sender As Object, e As RoutedEventArgs)
            Me.RaiseEvent(New RoutedPropertyChangedEventArgs(Of Player)(SelectedPlayer, SelectedPlayer, PlayerDetailRequestedEvent))
    End Sub