My class cannot be used as a parameter of type "TEventArgs" in a generic type or method "System.EventHandler <TEventArgs>" in .Net 4
I am trying to learn about EventHandler and I need to use a notification project. Here is the project link: https://codeload.github.com/mike-eason/WPF_ToastNotifications/zip/master
All I did was change the .Net framework from 4.5 to 4
And I ran into this error:
My class cannot be used as a parameter of type 'TEventArgs' in the generic type or method 'System.EventHandler'
ToastNotification Class:
[TemplatePart(Name = "PART_DismissButton", Type = typeof(Button))]
public class ToastNotification : ContentControl
{
public event EventHandler Dismissed;
public string Title
{
get { return (string)GetValue(TitleProperty); }
set { SetValue(TitleProperty, value); }
}
public static readonly DependencyProperty TitleProperty =
DependencyProperty.Register("Title", typeof(string), typeof(ToastNotification));
public string Message
{
get { return (string)GetValue(MessageProperty); }
set { SetValue(MessageProperty, value); }
}
public static readonly DependencyProperty MessageProperty =
DependencyProperty.Register("Message", typeof(string), typeof(ToastNotification));
public ToastTypes ToastType
{
get { return (ToastTypes)GetValue(ToastTypeProperty); }
set { SetValue(ToastTypeProperty, value); }
}
public static readonly DependencyProperty ToastTypeProperty =
DependencyProperty.Register("ToastType", typeof(ToastTypes), typeof(ToastNotification), new PropertyMetadata(new PropertyChangedCallback(OnToastTypeChanged)));
private static void OnToastTypeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ToastNotification toast = (ToastNotification)d;
toast.RefreshBackgroundColour();
}
private void RefreshBackgroundColour()
{
switch (ToastType)
{
case ToastTypes.Success:
Background = ColourSuccess;
break;
case ToastTypes.Error:
Background = ColourDanger;
break;
case ToastTypes.Info:
Background = ColourInfo;
break;
case ToastTypes.Warning:
Background = ColourWarning;
break;
}
}
public bool IsPersistent
{
get { return (bool)GetValue(IsPersistentProperty); }
set { SetValue(IsPersistentProperty, value); }
}
public static readonly DependencyProperty IsPersistentProperty =
DependencyProperty.Register("IsPersistent", typeof(bool), typeof(ToastNotification));
public double FontSizeTitle
{
get { return (double)GetValue(FontSizeTitleProperty); }
set { SetValue(FontSizeTitleProperty, value); }
}
public static readonly DependencyProperty FontSizeTitleProperty =
DependencyProperty.Register("FontSizeTitle", typeof(double), typeof(ToastNotification));
public Brush ColourSuccess
{
get { return (Brush)GetValue(ColourSuccessProperty); }
set { SetValue(ColourSuccessProperty, value); }
}
public static readonly DependencyProperty ColourSuccessProperty =
DependencyProperty.Register("ColourSuccess", typeof(Brush), typeof(ToastNotification));
public Brush ColourDanger
{
get { return (Brush)GetValue(ColourDangerProperty); }
set { SetValue(ColourDangerProperty, value); }
}
public static readonly DependencyProperty ColourDangerProperty =
DependencyProperty.Register("ColourDanger", typeof(Brush), typeof(ToastNotification));
public Brush ColourInfo
{
get { return (Brush)GetValue(ColourInfoProperty); }
set { SetValue(ColourInfoProperty, value); }
}
public static readonly DependencyProperty ColourInfoProperty =
DependencyProperty.Register("ColourInfo", typeof(Brush), typeof(ToastNotification));
public Brush ColourWarning
{
get { return (Brush)GetValue(ColourWarningProperty); }
set { SetValue(ColourWarningProperty, value); }
}
public static readonly DependencyProperty ColourWarningProperty =
DependencyProperty.Register("ColourWarning", typeof(Brush), typeof(ToastNotification));
static ToastNotification()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(ToastNotification), new FrameworkPropertyMetadata(typeof(ToastNotification)));
}
public ToastNotification()
{
this.Loaded += ToastNotification_Loaded;
}
private void ToastNotification_Loaded(object sender, RoutedEventArgs e)
{
Storyboard sb = this.FindResource("ToastScaleInStoryboard") as Storyboard;
Storyboard.SetTarget(sb, this);
sb.Begin();
}
public override void OnApplyTemplate()
{
ButtonBase PART_DismissButton = this.GetTemplateChild("PART_DismissButton") as ButtonBase;
if (PART_DismissButton != null)
PART_DismissButton.Click += OnDismissed;
base.OnApplyTemplate();
RefreshBackgroundColour();
}
protected void OnDismissed(object sender, RoutedEventArgs e)
{
var eh = Dismissed;
if (eh != null)
eh(this, EventArgs.Empty);
}
}
Toast Class:
internal class Toast
{
public event EventHandler<ToastNotification> ToastClosing;
private DispatcherTimer _Timer;
private ToastNotification _Notification;
public Toast(ToastNotification notification)
{
_Notification = notification;
_Notification.Dismissed += Notification_Dismissed;
}
private void Notification_Dismissed(object sender, EventArgs e)
{
OnToastClosing();
}
private void Timer_Tick(object sender, EventArgs e)
{
//Stop and close the window.
_Timer.Stop();
OnToastClosing();
}
public void Show(TimeSpan displayTime)
{
//Only start the timer if the notification is not persistent.
if (!_Notification.IsPersistent)
{
//Set up the timer
_Timer = new DispatcherTimer();
_Timer.Interval = displayTime;
_Timer.Tick += Timer_Tick;
//Start the timer
_Timer.Start();
}
}
protected void OnToastClosing()
{
//Unsubscribe from the on dismiss event first (to avoid memory leaks)
_Notification.Dismissed -= Notification_Dismissed;
var eh = ToastClosing;
if (eh != null)
eh(this, _Notification);
}
}
+4
2 answers
System.EventHandler<T> .NET 4.5. 4.5 :
public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e)
where TEventArgs : EventArgs;
public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e);
, where ... . .NET 4.5 , , EventArgs. ToastNotification , , , . .NET 4.5+ - , .
ToastClosing
public event Action<object, ToastNotification> ToastClosing;
.
+2