I've been teaching myself WPF through Sells/Griffiths' "Programming WPF", and I've found it a great resource, but I'm trying to take some of the concepts they've introduced me to and go a step further, and I'm running into a conceptual snag on how to put the pieces together to accomplish what I'm trying to do.
In this exercise, I'm trying to create self-terminating animations; FrameworkElements that are created by Events, perform an animation, and then delete themselves. I'm having problems figuring out how to call back to the parent FrameworkElement from the animation.Completed event.
I asked this question originally just using DoubleAnimations that were uncontained and not part of the Storyboard. I have since added the Storyboard, and made the Storyboard and rectangle resources so they can be reused easily.
Here's what I have so far:
.xaml:
<Window.Resources>
<Storyboard x:Key="GrowSquare" x:Shared="False">
<DoubleAnimation Storyboard.TargetProperty="(Canvas.Top)" By="-50" Duration="0:0:2"/>
<DoubleAnimation Storyboard.TargetProperty="(Canvas.Left)" By="-50" Duration="0:0:2"/>
<DoubleAnimation Storyboard.TargetProperty="(Ellipse.Width)" By="100" Duration="0:0:2"/>
<DoubleAnimation Storyboard.TargetProperty="(Ellipse.Height)" By="100" Duration="0:0:2"/>
</Storyboard>
<Rectangle x:Key="MyRect" x:Shared="False" Width="20" Height="20">
</Rectangle>
</Window.Resources>
<Canvas x:Name="myCanvas" MouseMove="myCanvas_MouseMove" Background="White"/>
.cs:
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
lastFire = DateTime.Now;
}
DateTime lastFire;
private void myCanvas_MouseMove(object sender, MouseEventArgs e)
{
DateTime nowTime = DateTime.Now;
TimeSpan T = nowTime.Subtract(lastFire);
if (T.TotalMilliseconds > 200)
{
lastFire = nowTime;
Random Rand = new Random();
Rectangle myRect = (Rectangle)FindResource("MyRect");
myRect.Fill = new SolidColorBrush(Color.FromRgb((byte)Rand.Next(256), (byte)Rand.Next(256), (byte)Rand.Next(256)));
Point myLoc = e.GetPosition(myCanvas);
Canvas.SetLeft(myRect, myLoc.X - 10);
Canvas.SetTop(myRect, myLoc.Y - 10);
myCanvas.Children.Add(myRect);
Storyboard SB = (Storyboard)FindResource("GrowSquare");
SB.Completed += new EventHandler(SB_Completed);
SB.Begin(myRect);
}
}
void SB_Completed(object sender, EventArgs e)
{
myCanvas.Children.RemoveAt(0);
}
}
This works, but not in the way I'd like it. Since the canvas is empty, and all animations are the same length, when an animation finishes, it will always be the one that was called on the first child of the canvas.
However, I'd like to implement animaitons that take a random amount of time, meaning that animations will not always start and end in the same order. Somehow in the SB_Completed event, I'd like to access the control that it was being called upon, but I can't seem to find the path to it yet.
Is there a way to get from the Media.Animation.ClockGroup that calls the SB_Completed event to the control that the animation is being called on?
change the line where you assign the event handler to this:
SB.Completed += (s,e) => myCanvas.Children.Remove(myRect);
Related
I have this code. This is just an example. I want to do it with code. How to animate the Foreground property of multiple "Run" elements in a TextBlock?
<Page
x:Class="AnimationTest.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="using:AnimationTest"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
mc:Ignorable="d">
<Grid>
<TextBlock
x:Name="_textBlockElement"
HorizontalAlignment="Center"
VerticalAlignment="Center"
FontSize="72"><Run x:Name="_run1" Text="Hel" /><Run Text="lo" />
<TextBlock.Triggers>
<EventTrigger>
<BeginStoryboard>
<Storyboard x:Name="ColorStoryboard">
<ColorAnimation
AutoReverse="True"
RepeatBehavior="Forever"
Storyboard.TargetName="_textBlockElement"
Storyboard.TargetProperty="(TextBlock.Foreground).(SolidColorBrush.Color)"
To="Red"
Duration="0:0:2" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</TextBlock.Triggers>
</TextBlock>
</Grid>
</Page>
Oke, so this took quite some sorting out, but turned out to be quite doable.
The key is to create two storyboards in code behind with the correct animations and then add those storyboards to the resources of any parent of the Run's.
Let's start of with the XAML code, which is pretty simple:
<Grid>
<TextBlock x:Name="TestBlock"
HorizontalAlignment="Center" VerticalAlignment="Center"
PointerEntered="TestBlock_PointerEntered"
PointerExited="TestBlock_PointerExited">
<Run x:Name="Run1" Text="Test1" Foreground="Blue"/>
<Run x:Name="Run2" Text="Test2" Foreground="Green"/>
<!-- ... -->
</TextBlock>
</Grid>
For simplicity I have already defined the names and foregrounds of the Run's.
Now we need to define the storyboards and animations in code behind.
I've chosen to do this in the constructor (after InitializeComponent()!). In theory you should be able to also paste this code in the Page_Loaded event.
public MainPage()
{
InitializeComponent();
SetupStoryBoards();
}
void SetupStoryBoards()
{
// Define duration and storyboards to red and original color
var duration = new Duration(TimeSpan.FromSeconds(1));
var toRedStory = new Storyboard { Duration = duration };
// completed events can be subscribed to, to register when animation is done
//toRedStory.Completed += Story_Completed;
var toOriginalStory = new Storyboard { Duration = duration };
//toOriginalStory.Completed += ToOriginalStory_Completed;
foreach (Run r in TestBlock.Inlines)
{
// Filter out any inlines that are not a named Run
if (string.IsNullOrEmpty(r.Name))
continue;
// Define the animations
var toRedAnim = new ColorAnimation
{
Duration = duration,
To = Colors.Red,
EnableDependentAnimation = true
};
var toOriginalAnim = new ColorAnimation
{
Duration = duration,
To = (r.Foreground as SolidColorBrush).Color, // Causes animation to go back to original foreground color of Run
EnableDependentAnimation = true
};
// Add animations to the storyboards and associate animations with the Run
toRedStory.Children.Add(toRedAnim);
toOriginalStory.Children.Add(toOriginalAnim);
Storyboard.SetTargetName(toRedAnim, r.Name);
Storyboard.SetTargetName(toOriginalAnim, r.Name);
Storyboard.SetTargetProperty(toRedAnim, "(Run.Foreground).(SolidColorBrush.Color)");
Storyboard.SetTargetProperty(toOriginalAnim, "(Run.Foreground).(SolidColorBrush.Color)");
}
// Add the storyboards to the resources of any parent of the Run's for easy retrieval later and to make the animations find the Run's
// I choose the resources of the textblock that contains the Run's
TestBlock.Resources.Add("toRedStory", toRedStory);
TestBlock.Resources.Add("toOriginalStory", toOriginalStory);
}
Now to execute the animations, we add the PointerEntered and PointerExited eventhandlers, and begin the correct storyboards there:
private void TextBlock_PointerEntered(object sender, PointerRoutedEventArgs e)
{
var story = TestBlock.Resources["toRedStory"] as Storyboard;
story.Begin();
}
private void TextBlock_PointerExited(object sender, PointerRoutedEventArgs e)
{
var story = TestBlock.Resources["toOriginalStory"] as Storyboard;
story.Begin();
}
You should be able to extend this wherever needed, however I have found that EnableDependentAnimation must be set to true since otherwise it won't work.
I am trying to make a WPF application using the MVVM pattern.
I now want to be able to navigate between ViewModels, and for that I've used this article: https://rachel53461.wordpress.com/2011/12/18/navigation-with-mvvm-2/
Basically, the Main Window Resources contain DataTemplates for each View Model linking it to it's view, and a Content Control bound to CurrentPageViewModel like this:
<Window.Resources>
<DataTemplate DataType="{x:Type ViewModels:HomeViewModel}">
<Views:HomeView />
</DataTemplate>
<DataTemplate DataType="{x:Type ViewModels:VaultViewModel}">
<Views:VaultView />
</DataTemplate>
<DataTemplate DataType="{x:Type ViewModels:VaultsViewModel}">
<Views:VaultsView />
</DataTemplate>
</Window.Resources>
<ContentControl Content="{Binding CurrentPageViewModel}" />
In the constructor of the Main Window I set CurrentPageViewModel to a new instance of my home screen view model and when I want to navigate, all I need to do is change CurrentPageViewModel and WPF will do the rest because of my use of INotifyPropertyChanged.
I am sending Change Page requests to the main window from my View Models by copying the code from MVVM Light's messenger implementing the Mediator pattern, and this works fine, except when I have Storyboards playing.
I have two very nice buttons inside of my home page, which will grow a bit when you hover over them:
<Button Style="{DynamicResource MaterialButton}" Width="400px" Height="400px" Margin="15px"
FontSize="24" FontFamily="Roboto" FontWeight="Bold"
Effect="{DynamicResource HomeButtonDropShadowEffect}" Command="{Binding DisplayVaultsView}"
Content="Vaults">
<!--#region button effects -->
<Button.RenderTransform>
<ScaleTransform x:Name="scaleTransform" CenterX="200" CenterY="200" ScaleX="1.0" ScaleY="1.0"/>
</Button.RenderTransform>
<Button.Triggers>
<EventTrigger RoutedEvent="Button.MouseEnter">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="scaleTransform"
Storyboard.TargetProperty="ScaleX"
To="1.08" Duration="0:0:0.1"/>
<DoubleAnimation
Storyboard.TargetName="scaleTransform"
Storyboard.TargetProperty="ScaleY"
To="1.08" Duration="0:0:0.1"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
<EventTrigger RoutedEvent="Button.MouseLeave">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="scaleTransform"
Storyboard.TargetProperty="ScaleX"
To="1.0" Duration="0:0:0.1" FillBehavior="Stop"/>
<DoubleAnimation
Storyboard.TargetName="scaleTransform"
Storyboard.TargetProperty="ScaleY"
To="1.0" Duration="0:0:0.1" FillBehavior="Stop"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Button.Triggers>
<!--#endregion-->
</Button>
As you can see, the button's Command is set to DisplayVaultsView, which is a method inside of the HomeViewModel which sends the Change Page request to the Main Window.
Without these storyboards inside the button, this works just fine and the new page is displayed. However, with the storyboards, the following error is thrown once I click the button:
System.InvalidOperationException: ''scaleTransform' name cannot be found in the name scope of 'System.Windows.Controls.Button'.'
This has led me to believe that the animation is still attempting to play, but since the Button is not in the current context anymore it can't find the property it's supposed to animate.
It's also important to note that the HomeViewModel is not thrown away when you navigate to another page, I've written my own Navigator class which keeps track of the ViewModels so you can navigate forwards/backwards without losing any changes (and without having to reload everything).
I'd like to know how I can solve this error, but it has also led me to the realization that I might need to "unload" ViewModels when switching to another one. I'm currently just keeping all ViewModel references inside of a List inside the Navigator class. So my other question is, should I "unload" the ViewModels when switching to another, and how?
I found a solution which works, but I'm not sure as to why it worked.
I removed all of the XAML concerned with the animations, and moved the animating to the code-behind in HomeView.xaml.
Here's the code:
public partial class HomeView : UserControl
{
private Storyboard _mouseEnterStoryboard;
private Storyboard _mouseLeaveStoryboard;
private DoubleAnimation _scaleX_In;
private DoubleAnimation _scaleY_In;
private DoubleAnimation _scaleX_Out;
private DoubleAnimation _scaleY_Out;
public HomeView()
{
InitializeComponent();
_mouseEnterStoryboard = new Storyboard();
ScaleTransform scaleVaultsButton = new ScaleTransform(1.0, 1.0);
ScaleTransform scaleFilesButton = new ScaleTransform(1.0, 1.0);
VaultsButton.RenderTransformOrigin = new Point(0.5, 0.5);
VaultsButton.RenderTransform = scaleVaultsButton;
FilesButton.RenderTransformOrigin = new Point(0.5, 0.5);
FilesButton.RenderTransform = scaleFilesButton;
_scaleX_In = new DoubleAnimation()
{
Duration = TimeSpan.FromMilliseconds(100),
From = 1.0,
To = 1.08
};
_scaleY_In = new DoubleAnimation()
{
Duration = TimeSpan.FromMilliseconds(100),
From = 1.0,
To = 1.08
};
_mouseEnterStoryboard.Children.Add(_scaleX_In);
_mouseEnterStoryboard.Children.Add(_scaleY_In);
Storyboard.SetTargetProperty(_scaleX_In, new PropertyPath("RenderTransform.ScaleX"));
Storyboard.SetTargetProperty(_scaleY_In, new PropertyPath("RenderTransform.ScaleY"));
_mouseLeaveStoryboard = new Storyboard();
_scaleX_Out = new DoubleAnimation()
{
Duration = TimeSpan.FromMilliseconds(100),
From = 1.08,
To = 1.0
};
_scaleY_Out = new DoubleAnimation()
{
Duration = TimeSpan.FromMilliseconds(100),
From = 1.08,
To = 1.0
};
_mouseLeaveStoryboard.Children.Add(_scaleX_Out);
_mouseLeaveStoryboard.Children.Add(_scaleY_Out);
Storyboard.SetTargetProperty(_scaleX_Out, new PropertyPath("RenderTransform.ScaleX"));
Storyboard.SetTargetProperty(_scaleY_Out, new PropertyPath("RenderTransform.ScaleY"));
VaultsButton.MouseEnter += new MouseEventHandler(Button_MouseEnter);
VaultsButton.MouseLeave += new MouseEventHandler(Button_MouseLeave);
FilesButton.MouseEnter += new MouseEventHandler(Button_MouseEnter);
FilesButton.MouseLeave += new MouseEventHandler(Button_MouseLeave);
}
public void Button_MouseEnter(object sender, MouseEventArgs e)
{
Storyboard.SetTarget(_scaleX_In, (Button)sender);
Storyboard.SetTarget(_scaleY_In, (Button)sender);
_mouseEnterStoryboard.Begin();
}
public void Button_MouseLeave(object sender, MouseEventArgs e)
{
Storyboard.SetTarget(_scaleX_Out, (Button)sender);
Storyboard.SetTarget(_scaleY_Out, (Button)sender);
_mouseLeaveStoryboard.Begin();
}
}
I'm not sure as to why this does work and the XAML version doesn't, so I'd still like an answer to that question.
I'm making a WPF application using C# and Visual Studio and I need a button to jump to a random location in the window when the mouse hovers over it. I then need the same thing to happen when you hover over it again. I also don't need an animation, just for it to jump there.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void butNo_MouseEnter(object sender, MouseEventArgs e)
{
}
}
I tried this but it didn't work and is also an animation:
<Button.Triggers>
<EventTrigger RoutedEvent="Button.Click">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation From="0" To="100" Duration="0:0:2" Storyboard.TargetProperty="(Canvas.Left)" AutoReverse="False" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Button.Triggers>
Any help would be much appreciated, thanks.
Edit:
Tried this but 'Location' comes with error code CS1061 in VS.
private void butNo_MouseEnter(object sender, MouseEventArgs e)
{
Random x = new Random();
Point pt = new Point(int.Parse(x.Next(200).ToString()), int.Parse(x.Next(250).ToString()));
butNo.Location = pt;
}
Here's a solution using a Canvas and animations.
<Canvas Name="cnv">
<Button Name="btn"
Content="Click Me!"
IsTabStop="False"
Canvas.Left="0"
Canvas.Top="0"
MouseEnter="Button_MouseEnter"/>
</Canvas>
And the code-behind:
Random rnd = new Random();
private void Button_MouseEnter(object sender, MouseEventArgs e)
{
//Work out where the button is going to move to.
double newLeft = rnd.Next(Convert.ToInt32(cnv.ActualWidth - btn.ActualWidth));
double newTop = rnd.Next(Convert.ToInt32(cnv.ActualHeight - btn.ActualHeight));
//Create the animations for left and top
DoubleAnimation animLeft = new DoubleAnimation(Canvas.GetLeft(btn), newLeft, new Duration(TimeSpan.FromSeconds(1)));
DoubleAnimation animTop = new DoubleAnimation(Canvas.GetTop(btn), newTop, new Duration(TimeSpan.FromSeconds(1)));
//Set an easing function so the button will quickly move away, then slow down
//as it reaches its destination.
animLeft.EasingFunction = new CubicEase() { EasingMode = EasingMode.EaseOut };
animTop.EasingFunction = new CubicEase() { EasingMode = EasingMode.EaseOut };
//Start the animation.
btn.BeginAnimation(Canvas.LeftProperty, animLeft, HandoffBehavior.SnapshotAndReplace);
btn.BeginAnimation(Canvas.TopProperty, animTop, HandoffBehavior.SnapshotAndReplace);
}
And here is a gif of it in action.
I really don't normally like doing homework problems for people, but I'm bored at work so here you go.
You need to just use the Margin and update the Left and Top values to random numbers within the height/width of your grid so it doesn't go outside of the view.
Also, make sure to use IsTabStop="False" otherwise, you could tab to it and still click it.
So, for the simplest case using codebehind:
XAML:
<Window x:Class="mousemove.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid x:Name="Grid1">
<Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="0,0,0,0" Name="button1" Width="75" MouseEnter="button1_MouseEnter" IsTabStop="False"/>
</Grid>
MainWindow.xaml.cs
private void button1_MouseEnter(object sender, MouseEventArgs e)
{
int maxLeft = Convert.ToInt32(Grid1.ActualWidth - button1.Width);
int maxTop = Convert.ToInt32(Grid1.ActualHeight - button1.Height);
Random rand = new Random();
button1.Margin = new Thickness(rand.Next(maxLeft), rand.Next(maxTop), 0, 0);
}
this might sounds very simple, but I couldn't find a way to do it.
I just want a blinking text in TextBlock. Is there a way to do it easily?
The only way I can think of is to use timer and change the TextBlock foreground manually. Surely there is an easy way to do it. I am just not able to figure it out.
Thanks!
You could declare a Storyboard animation in your XAML markup which blinks the text forever:
<TextBlock Text="I'm Blinking!">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Resources>
<Storyboard x:Key="flashAnimation" >
<DoubleAnimation Storyboard.TargetProperty="Opacity" From="1" To="0" AutoReverse="True" Duration="0:0:0.5" RepeatBehavior="Forever" />
</Storyboard>
</Style.Resources>
</Style>
</TextBlock.Style>
</TextBlock>
This is using my experience from WPF and WinRT XAML, but I'm pretty sure that UWP uses the same Storyboard animations.
Here's Microsoft's handy reference on MSDN: Animations Overview.
Hope this helps!
From code behind (C#) you can do it for example with code like this:
Storyboard storyboard = new Storyboard();
storyboard.Duration = new Duration(TimeSpan.FromSeconds(10.0));
DoubleAnimation opacityAnimation = new DoubleAnimation()
{
From = 1.0,
To = 0.0,
BeginTime = TimeSpan.FromSeconds(5.0),
Duration = new Duration(TimeSpan.FromSeconds(5.0))
};
Storyboard.SetTarget(opacityAnimation, txtBlink);
Storyboard.SetTargetProperty(opacityAnimation, "Opacity");
storyboard.Children.Add(opacityAnimation);
storyboard.RepeatBehavior = RepeatBehavior.Forever;
storyboard.AutoReverse = true;
storyboard.Begin();
Assuming you have a textblock:
<TextBlock x:Name="txtBlink" FontSize="32">Some text</TextBlock>
For blinking text, I think timer is the easiest approach. (Though i understand you have the thought of using a timer & looking for an alternate, tier should actually serve the purpose)
Might be something like below can help you.
Timer timer = new Timer();
public void Blinker()
{
timer.Interval = 500;
timer.Start();
timer.Tick += new EventHandler(timer_tick);
}
void timer_tick(object sender, EventArgs e)
{
if(label3.ForeColor = System.Drawing.Color.Green)
{
label3.ForeColor = System.Drawing.Color.White;
}
else
{
label3.ForeColor = System.Drawing.Color.Green;
}
}
public void StopBlinker()
{
timer.Stop();
}
Now you can call the blinker method appropriately to make your text blink.
The following code is working fine.
<Window.Triggers>
<EventTrigger RoutedEvent="Window.Loaded">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Duration="0:0:.8" Storyboard.TargetProperty="Left" From="1920" To="0" AccelerationRatio=".1"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Window.Triggers>
But in this From and To values are static. I need to pass the values dynamically based system resolution. So i need it to be created in code behind. Is it possible to do ?
How to convert it to codebehind?
When working in code, you don't need Storyboard really, just animations for basic things, like you show in your question.
I made a little sample to show how easy it works.
This is the complete code behind of the mainwindow:
namespace WpfCSharpSandbox
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
WidenObject(150, TimeSpan.FromSeconds(1));
}
private void WidenObject(int newWidth, TimeSpan duration)
{
DoubleAnimation animation = new DoubleAnimation(newWidth, duration);
rctMovingObject.BeginAnimation(Rectangle.WidthProperty, animation);
}
}
}
This is how the XAML looks like:
<Window x:Class="WpfCSharpSandbox.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Sandbox" Height="350" Width="525">
<Grid Background="#333333">
<Rectangle x:Name="rctMovingObject" Fill="LimeGreen" Width="50" Height="50"/>
</Grid>
</Window>
Put this in a WPF app and see how it works, experiment with it and try other animations/properties.
Adding djerry's comment sample code would look like this:
var anim = new DoubleAnimation {
From = 1920,
To = 1,
};
wnd.BeginAnimation(Window.LeftProperty, anim);
and you would have to have this code in window loaded event handler. Hope this helps.
The question's example code was about animating the Window.Left property and I was looking for exact that case, but the given answer does work for an one-time use-case only.
Specifically: If the animation has been performed and the Window is then moved manually via drag&drop, the same animation procedure will not work again as desired. The animation will always use the end-coordinates of the recent animation run.
So if you moved the window, it will jump back before starting the new animation:
https://imgur.com/a/hxRCqm7
To solve that issue, it is required to remove any AnimationClock from the animated property after the animation is completed.
That is done by using ApplyAnimationClock or BeginAnimation with null as the second parameter:
public partial class MainWindow : Window
{
// [...]
private void ButtonMove_Click(object sender, RoutedEventArgs e)
{
AnimateWindowLeft(500, TimeSpan.FromSeconds(1));
}
private void AnimateWindowLeft(double newLeft, TimeSpan duration)
{
DoubleAnimation animation = new DoubleAnimation(newLeft, duration);
myWindow.Completed += AnimateLeft_Completed;
myWindow.BeginAnimation(Window.LeftProperty, animation);
}
private void AnimateLeft_Completed(object sender, EventArgs e)
{
myWindow.BeginAnimation(Window.LeftProperty, null);
// or
// myWindow.ApplyAnimationClock(Window.LeftProperty, null);
}
}
XAML:
<Window x:Class="WpfAppAnimatedWindowMove.MainWindow"
// [...]
Name="myWindow">
Result:
https://imgur.com/a/OZEsP6t
See also Remarks section of Microsoft Docs - HandoffBehavior Enum