PropertyMetadata Constructor (Object, PropertyChangedCallback, CoerceValueCallback) (System.Windows)

MSDN Library
.NET Development
.NET Framework 3.5
.NET Framework Class Library
System.Windows Namespace
PropertyMetadata Class
PropertyMetadata Constructor

PropertyMetadata Constructor
PropertyMetadata Constructor (Object)
PropertyMetadata Constructor (PropertyChangedCallback)
PropertyMetadata Constructor (Object, PropertyChangedCallback)

PropertyMetadata Constructor (Object, PropertyChangedCallback, CoerceValueCallback)

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PropertyMetadata Constructor (Object, PropertyChangedCallback, CoerceValueCallback)
This page is specific to:.NET Framework Version:3.03.54.0

.NET Framework Class Library

PropertyMetadata Constructor (Object, PropertyChangedCallback, CoerceValueCallback)

Initializes a new instance of the PropertyMetadata class with the specified default value and callbacks.

Namespace: System.Windows
Assembly: WindowsBase (in WindowsBase.dll)

Syntax

C++

JScript

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'Usage

Dim defaultValue As Object
Dim propertyChangedCallback As PropertyChangedCallback
Dim coerceValueCallback As CoerceValueCallback

Dim instance As New PropertyMetadata(defaultValue, _
    propertyChangedCallback, coerceValueCallback)

'Declaration

Public Sub New ( _
    defaultValue As Object, _
    propertyChangedCallback As PropertyChangedCallback, _
    coerceValueCallback As CoerceValueCallback _
)

XAML

You cannot use constructors in XAML.

Parameters

defaultValue: Type: System..::.Object
The default value of the dependency property, usually provided as a value of some specific type.

propertyChangedCallback: Type: System.Windows..::.PropertyChangedCallback
Reference to a handler implementation that is to be called by the property system whenever the effective value of the property changes.

coerceValueCallback: Type: System.Windows..::.CoerceValueCallback
Reference to a handler implementation that is to be called whenever the property system calls CoerceValue against this property.

Exceptions

Exception	Condition
ArgumentException	defaultValue cannot be set to the value UnsetValue; see Remarks.

Remarks

If you want to specify a CoerceValueCallback but not a PropertyChangedCallback, you can pass nullNothingnullptra null reference (Nothing in Visual Basic) for the propertyChangedCallback parameter.

The type of the value provided for defaultValue must be match or be related to the type specified in the original registration of the dependency property that this metadata will be applied to. Mismatches between metadata default value type and the type of the dependency property it is being applied to can be difficult to debug, because the mismatch is not detectable during compilation (the mismatch will raise a run-time exception).

Although it is the default per the parameterless constructor, a defaultValue of UnsetValue cannot be specified. Attempting to do so will raise an exception.

Examples

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static PropertyMetadata pm;


...


pm = new PropertyMetadata(
    Double.NaN,
    new PropertyChangedCallback(OnCurrentReadingChanged),
    new CoerceValueCallback(CoerceCurrentReading)
);

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0

Reference

PropertyMetadata Class

PropertyMetadata Members

PropertyMetadata Overload

System.Windows Namespace

Other Resources

Custom Dependency Properties

Dependency Property Callbacks and Validation

Dependency Property Metadata