DefaultPropertyAttribute Class (System.ComponentModel)

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DefaultPropertyAttribute Class

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Specifies the default property for a component.

Inheritance Hierarchy

System.Object
  System.Attribute
    System.ComponentModel.DefaultPropertyAttribute

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

Visual Basic
<AttributeUsageAttribute(AttributeTargets.Class)> _
Public NotInheritable Class DefaultPropertyAttribute _
	Inherits Attribute
C#
[AttributeUsageAttribute(AttributeTargets.Class)]
public sealed class DefaultPropertyAttribute : Attribute
Visual C++
[AttributeUsageAttribute(AttributeTargets::Class)]
public ref class DefaultPropertyAttribute sealed : public Attribute
F#
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Class)>]
type DefaultPropertyAttribute =  
    class
        inherit Attribute
    end

The DefaultPropertyAttribute type exposes the following members.

Constructors

  Name Description
Public method DefaultPropertyAttribute Initializes a new instance of the DefaultPropertyAttribute class.
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Properties

  Name Description
Public property Name Gets the name of the default property for the component this attribute is bound to.
Public property TypeId When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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Methods

  Name Description
Public method Equals Returns whether the value of the given object is equal to the current DefaultPropertyAttribute. (Overrides Attribute.Equals(Object).)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Returns the hash code for this instance. (Overrides Attribute.GetHashCode().)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttribute When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method Match When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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Fields

  Name Description
Public field Static member Default Specifies the default value for the DefaultPropertyAttribute, which is null. This static field is read-only.
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Explicit Interface Implementations

  Name Description
Explicit interface implemetation Private method _Attribute.GetIDsOfNames Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfo Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfoCount Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.Invoke Provides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Remarks

Use the Name property to get the name of the default property.

For more information, see Extending Metadata Using Attributes.

Examples

The following example defines a control named MyControl. The class is marked with a DefaultPropertyAttribute that specifies MyProperty as the default property.

Visual Basic

<DefaultProperty("MyProperty")> _
Public Class MyControl
    Inherits Control

    Public Property MyProperty() As Integer
        Get
            ' Insert code here.
            Return 0
        End Get
        Set
            ' Insert code here.
        End Set 
    End Property
    ' Insert any additional code.
End Class 'MyControl


C#

[DefaultProperty("MyProperty")]
 public class MyControl : Control {

    public int MyProperty {
       get {
          // Insert code here.
          return 0;
       }
       set {
          // Insert code here.
       }
    }

    // Insert any additional code.

 }


Visual C++

[DefaultProperty("MyProperty")]
ref class MyControl: public Control
{
public:

   property int MyProperty 
   {
      int get()
      {
         // Insert code here.
         return 0;
      }

      void set( int value )
      {
         // Insert code here.
      }
   }
   // Insert any additional code.
};


The next example creates an instance of MyControl. Then it gets the attributes for the class, extracts the DefaultPropertyAttribute, and prints the name of the default property.

Visual Basic

Public Shared Function Main() As Integer
    ' Creates a new control.
    Dim myNewControl As New MyControl()

    ' Gets the attributes for the collection.
    Dim attributes As AttributeCollection = TypeDescriptor.GetAttributes(myNewControl)

    ' Prints the name of the default property by retrieving the
    ' DefaultPropertyAttribute from the AttributeCollection. 
    Dim myAttribute As DefaultPropertyAttribute = _
        CType(attributes(GetType(DefaultPropertyAttribute)), DefaultPropertyAttribute)
    Console.WriteLine(("The default property is: " + myAttribute.Name))
    Return 0
End Function 'Main



C#

public static int Main() {
    // Creates a new control.
    MyControl myNewControl = new MyControl();

    // Gets the attributes for the collection.
    AttributeCollection attributes = TypeDescriptor.GetAttributes(myNewControl);

    /* Prints the name of the default property by retrieving the 
     * DefaultPropertyAttribute from the AttributeCollection. */
    DefaultPropertyAttribute myAttribute = 
       (DefaultPropertyAttribute)attributes[typeof(DefaultPropertyAttribute)];
    Console.WriteLine("The default property is: " + myAttribute.Name);

    return 0;
 }


Visual C++

int main()
{
   // Creates a new control.
   Form1::MyControl^ myNewControl = gcnew Form1::MyControl;

   // Gets the attributes for the collection.
   AttributeCollection^ attributes = TypeDescriptor::GetAttributes( myNewControl );

   /* Prints the name of the default property by retrieving the 
       * DefaultPropertyAttribute from the AttributeCollection. */
   DefaultPropertyAttribute^ myAttribute = dynamic_cast<DefaultPropertyAttribute^>(attributes[ DefaultPropertyAttribute::typeid ]);
   Console::WriteLine( "The default property is: {0}", myAttribute->Name );
   return 0;
}


Version Information

.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
Platforms

Windows 8 Consumer Preview, Windows Server 8 Beta, Windows 7, Windows Server 2008 SP2, 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.

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.
See Also

Reference