Timeline.BeginTime Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets the time at which this Timeline should begin.
public:
property Nullable<TimeSpan> BeginTime { Nullable<TimeSpan> get(); void set(Nullable<TimeSpan> value); };public TimeSpan? BeginTime { get; set; }member this.BeginTime : Nullable<TimeSpan> with get, setPublic Property BeginTime As Nullable(Of TimeSpan)Property Value
The time at which this Timeline should begin, relative to its parent's BeginTime. If this timeline is a root timeline, the time is relative to its interactive begin time (the moment at which the timeline was triggered). This value may be positive, negative, or null; a null value means the timeline never plays. The default value is zero.
Examples
A timeline's BeginTime property determines the beginning of a timeline's active period. If the timeline has a parent timeline, the BeginTime property determines how long it takes the timeline to start after its parent starts. If the timeline is a root timeline (a Storyboard, for example), the BeginTime property determines how long the timeline takes to start playing after it is triggered.
The following example shows several different timelines with different BeginTime settings.
<!-- This example shows how the BeginTime property determines when a timeline starts.
Several rectangles are animated by DoubleAnimations with identical
durations and target values, but with different
BeginTime settings. -->
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
WindowTitle="BeginTime Example">
<StackPanel Margin="20">
<!-- The rectangles to animate. -->
<Rectangle Name="DefaultBeginTimeRectangle"
Width="20" Height="20" Fill="Blue" />
<Rectangle Name="DelayedBeginTimeRectangle"
Width="20" Height="20" Fill="Blue" />
<Rectangle Name="DelayedAnimationWithDelayedParentRectangle"
Width="20" Height="20" Fill="Blue" />
<Rectangle Name="NegativeBeginTimeExampleRectangle"
Width="20" Height="20" Fill="Blue" />
<!-- Create a button to start the animations. -->
<Button Margin="20" Content="Start Animations">
<Button.Triggers>
<EventTrigger RoutedEvent="Button.Click">
<BeginStoryboard>
<Storyboard>
<!-- This animation starts as soon as the button is clicked, because it
has a BeginTime of 0. -->
<DoubleAnimation
Storyboard.TargetName="DefaultBeginTimeRectangle"
Storyboard.TargetProperty="Width"
BeginTime="0:0:0" From="100" To="600" Duration="0:0:5" />
<!-- This animation starts 5 seconds after the button is clicked. -->
<DoubleAnimation
Storyboard.TargetName="DelayedBeginTimeRectangle"
Storyboard.TargetProperty="Width"
BeginTime="0:0:5" From="100" To="600" Duration="0:0:5" />
<ParallelTimeline BeginTime="0:0:5">
<!-- This animation starts 10 seconds after the button is clicked,
because its parent has a BeginTime of 5 seconds and it has
a BeginTime of 5 seconds: 5 + 5 = 10. -->
<DoubleAnimation
Storyboard.TargetName="DelayedAnimationWithDelayedParentRectangle"
Storyboard.TargetProperty="Width"
BeginTime="0:0:5" From="100" To="600" Duration="0:0:5" />
</ParallelTimeline>
<!-- This animation starts as soon as the button is clicked, but
it animates from 350 to 600 instead of from 100 to 600
because of its negative BeginTime. The negative BeginTime
setting advances the animation, so that it behaves as though
it had already been playing for 2.5 seconds as soon as it is
started. -->
<DoubleAnimation
Storyboard.TargetName="NegativeBeginTimeExampleRectangle"
Storyboard.TargetProperty="Width"
BeginTime="-0:0:2.5" From="100" To="600" Duration="0:0:5" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Button.Triggers>
</Button>
<!-- This example demonstrates how the BeginTime property works on a root timeline. -->
<Rectangle Name="RootTimelineWithDelayedBeginTimeRectangle"
Width="20" Height="20" Fill="Blue" >
<Rectangle.Triggers>
<EventTrigger RoutedEvent="Rectangle.MouseLeftButtonDown">
<BeginStoryboard>
<Storyboard BeginTime="0:0:5">
<!-- This animation starts 5 seconds after the left mouse button
is pressed, because its parent storyboard (a root timeline)
has a BeginTime of 5 seconds. -->
<DoubleAnimation
Storyboard.TargetName="RootTimelineWithDelayedBeginTimeRectangle"
Storyboard.TargetProperty="Width"
BeginTime="0:0:0" From="100" To="600" Duration="0:0:2" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Rectangle.Triggers>
</Rectangle>
</StackPanel>
</Page>
Remarks
The BeginTime property is useful for creating timelines that play in a sequence: by increasing the BeginTime of successive timelines that share the same parent, you can stagger their play times.
Negative Values
A negative BeginTime value causes a Timeline to behave as though it started at some time in the past. For example, a Timeline with a BeginTime of negative 2.5 seconds and a Duration of 5 seconds will appear to be half-way finished when it starts.
BeginTime and SpeedRatio
The time described by the BeginTime property is measured in the timeline's parent's time. For example, a timeline with a BeginTime of 5 whose parent has a SpeedRatio of 2 actually starts after 2.5 seconds.
A timeline's own SpeedRatio setting does not affect its BeginTime. For example, a timeline with a BeginTime of 5 seconds, a SpeedRatio of 2, and a parent timeline with a SpeedRatio of 1 starts after 5 seconds, not 2.5.
Dependency Property Information
| Identifier field | BeginTimeProperty |
Metadata properties set to true |
None |
XAML Attribute Usage
<object BeginTime="[-][days.]hours:minutes:seconds[.fractionalSeconds]"/>
-or-
<object BeginTime="[-][days.]hours:minutes"/>
-or-
<object BeginTime="[-]days"/>
-or-
<object BeginTime="{x:Null Markup Extension}"/>
XAML Values
Items in square brackets ([ and ]) are optional.
days
System.Int32
A value greater than or equal to 0 that describes the number of days spanned by this begin time.
hours
System.Int32
A value between 0 and 23 that represents the number of hours spanned by this begin time.
minutes
System.Int32
A value between 0 and 59 that represents the number of minutes spanned by this begin time.
seconds
System.Int32
A value between 0 and 59 that represents the number of seconds spanned by this begin time.
fractionalSeconds
System.Int32
A value consisting of 1 to 7 digits that represents fractional seconds.
For the complete TimeSpan syntax, see the Remarks section of the Parse page.
