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DefaultValueAttribute Class

Specifies the default value for a property.

System.Object
  System.Attribute
    System.ComponentModel.DefaultValueAttribute

Namespace:  System.ComponentModel
Assembly:  System (in System.dll)

[AttributeUsageAttribute(AttributeTargets.All)]
public class DefaultValueAttribute : Attribute

The DefaultValueAttribute type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Boolean)Initializes a new instance of the DefaultValueAttribute class using a Boolean value.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Byte)Initializes a new instance of the DefaultValueAttribute class using an 8-bit unsigned integer.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Char)Initializes a new instance of the DefaultValueAttribute class using a Unicode character.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Double)Initializes a new instance of the DefaultValueAttribute class using a double-precision floating point number.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Int16)Initializes a new instance of the DefaultValueAttribute class using a 16-bit signed integer.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Int32)Initializes a new instance of the DefaultValueAttribute class using a 32-bit signed integer.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Int64)Initializes a new instance of the DefaultValueAttribute class using a 64-bit signed integer.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Object)Initializes a new instance of the DefaultValueAttribute class.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Single)Initializes a new instance of the DefaultValueAttribute class using a single-precision floating point number.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(String)Initializes a new instance of the DefaultValueAttribute class using a String.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsDefaultValueAttribute(Type, String)Initializes a new instance of the DefaultValueAttribute class, converting the specified value to the specified type, and using an invariant culture as the translation context.
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  NameDescription
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public propertySupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsValueGets the default value of the property this attribute is bound to.
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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsEqualsReturns whether the value of the given object is equal to the current DefaultValueAttribute. (Overrides Attribute.Equals(Object).)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeReturns the hash code for this instance. (Overrides Attribute.GetHashCode().)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodSetValueSets the default value for the property to which this attribute is bound.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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You can create a DefaultValueAttribute with any value. A member's default value is typically its initial value. A visual designer can use the default value to reset the member's value. Code generators can use the default values also to determine whether code should be generated for the member.

NoteNote

A DefaultValueAttribute will not cause a member to be automatically initialized with the attribute's value. You must set the initial value in your code.

For more information, see Extending Metadata Using Attributes.

The following example sets the default value of MyProperty to false.


private bool myVal=false;

[DefaultValue(false)]
 public bool MyProperty {
    get {
       return myVal;
    }
    set {
       myVal=value;
    }
 }

The next example checks the default value of MyProperty. First the code gets a PropertyDescriptorCollection with all the properties for the object. Next it indexes into the PropertyDescriptorCollection to get MyProperty. Then it returns the attributes for this property and saves them in the attributes variable.

The example then prints the default value by retrieving the DefaultValueAttribute from the AttributeCollection, and writing its name to the console screen.

// Gets the attributes for the property.
 AttributeCollection attributes = 
    TypeDescriptor.GetProperties(this)["MyProperty"].Attributes;

 /* Prints the default value by retrieving the DefaultValueAttribute 
  * from the AttributeCollection. */
 DefaultValueAttribute myAttribute = 
    (DefaultValueAttribute)attributes[typeof(DefaultValueAttribute)];
 Console.WriteLine("The default value is: " + myAttribute.Value.ToString());

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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