Duration Structure
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Represents the duration of time that a Timeline is active.
Namespace: System.Windows
Assembly: System.Windows (in System.Windows.dll)
Syntax
'Declaration
Public Structure Duration
public struct Duration
<object property="[days.]hours:minutes:seconds[.fractionalSeconds]"/>
-or-
<object property="Automatic" .../>
-or-
<object property="Forever" .../>
XAML Values
days
An integer value greater than or equal to 0 that specifies the number of days.hours
An integer value between 0 and 23 that specifies the number of hours. If you specify a Duration as a XAML attribute, an hours component is required, even if is 0.minutes
An integer value between 0 and 59 that specifies the number of minutes. Set hours:minutes components as 0:0 if you are setting only a seconds component.seconds
An integer value between 0 and 59 that specifies the number of seconds. Set hours:minutes components as 0:0 if you are setting only a seconds component.fractionalSeconds
Optional. A decimal value consisting of 1 to 7 positions past the decimal point, which specifies fractional seconds.Automatic
The literal string Automatic; see "Automatic and Forever" section in Remarks.Forever
The literal string Forever; see "Automatic and Forever" section in Remarks.
- In the grammar, [] indicates optional values, the [] are not literals. The : (colon) and . (period) characters are both literals, and delimit the h:m:s string form of a common timespan, or the optional days and fractionalSeconds values.
The Duration type exposes the following members.
Constructors
| Name | Description | |
|---|---|---|
.gif "Public method") .gif "Supported by Silverlight for Windows Phone") |
Duration | Initializes a new instance of the Duration structure with the supplied TimeSpan value. |
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Properties
| Name | Description | |
|---|---|---|
.gif "Public property") .gif "Static member") |
Automatic | Gets a Duration value that is automatically determined. |
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Forever | Gets a Duration value that represents an infinite interval. |
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HasTimeSpan | Gets a value that indicates if this Duration represents a TimeSpan value. |
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TimeSpan | Gets the TimeSpan value that this Duration represents. |
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Methods
| Name | Description | |
|---|---|---|
|
Add | Adds the value of the specified Duration to this Duration. |
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Compare | Compares one Duration value to another. |
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Equals(Duration) | Determines whether a specified Duration is equal to this Duration. |
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Equals(Object) | Determines whether a specified object is equal to a Duration. (Overrides ValueType.Equals(Object).) |
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Equals(Duration, Duration) | Determines whether two Duration values are equal. |
.gif "Protected method") |
Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
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GetHashCode | Gets a hash code for this object. (Overrides ValueType.GetHashCode().) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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Plus | Adds one Duration to this Duration. |
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Subtract | Subtracts the specified Duration from this Duration. |
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ToString | Converts a Duration to a String representation. (Overrides ValueType.ToString().) |
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Operators
| Name | Description | |
|---|---|---|
.gif "Public operator") |
Addition | Adds two Duration values together. |
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Equality | Determines whether two Duration cases are equal. |
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GreaterThan | Determines if one Duration is greater than another. |
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GreaterThanOrEqual | Determines whether a Duration is greater than or equal to another. |
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Implicit(TimeSpan to Duration) | Implicitly creates a Duration from a given TimeSpan. |
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Inequality | Determines if two Duration cases are not equal. |
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LessThan | Determines if a Duration is less than the value of another instance. |
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LessThanOrEqual | Determines if a Duration is less than or equal to another. |
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Subtraction | Subtracts the value of one Duration from another. |
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UnaryPlus | Returns the specified Duration. |
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Remarks
Specifying a Duration by only an integer without any time span literal characters such as : or . will result in a Duration of that number of days! This is seldom the intended result. Usually you specify animation durations in seconds. As such, the Duration string must include preceding 0 values for hours and minutes, along with the appropriate literal : characters as separators between hours, minutes and seconds. For instance, to specify a Duration of five seconds, the Duration string would be "0:0:5" ("0:0:05" is equivalent).
Duration can be set on either a Storyboard or an animation.
Automatic and Forever
Automatic and Forever are values that hold special meaning for a Duration property value, and are represented by the static properties Automatic and Forever in the managed API for Silverlight. For details, see Animation Overview.
The Automatic value applied in either XAML or code results in different behavior on the Storyboard as opposed to an animation. For Storyboard, the Automatic duration time behavior is equal to the end time of its latest ending child animation, such that no clipping of any of the child animation durations occurs. For animations, the Automatic duration is a time span of 1 second (0:0:1). This short duration is seldom desirable, but this default provides you the opportunity to see the animation start during testing. This is better debugging information than never having the animation run, as would occur with a 0 duration.
A Duration of Forever for an animation is part of a deprecated usage, and is seldom used. A Duration of Forever would result in an animation that never advanced from its starting value, no matter what values were provided for From/To, key frames, and so on. If you want an animation to repeat continuously, use RepeatBehavior="Forever", not Duration="Forever".
Duration does not support an object element syntax for Silverlight XAML, and you cannot declare a Duration as a resource dictionary item in XAML. In XAML you should always specify Duration -type properties in the attribute syntax shown here.
JavaScript API Notes
Creating a Duration in the JavaScript API for Silverlight is only possible through a type conversion syntax when setting a property such as Duration, with the value specified as a string. The string is generally specified in same format as TimeSpan. Duration can also take the literals Automatic and Forever.
In the managed API, you can create a Duration using the constructors.
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.