DefaultValueAttribute Class
 
System_CAPS_noteNote

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Specifies the default value for a property.

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

SystemObject
   SystemAttribute
    System.ComponentModelDefaultValueAttribute

[AttributeUsageAttribute(AttributeTargets.All)]
public class DefaultValueAttribute : Attribute
[AttributeUsageAttribute(AttributeTargets::All)]
public ref class DefaultValueAttribute : Attribute
[<AttributeUsageAttribute(AttributeTargets.All)>]
type DefaultValueAttribute = 
    class
        inherit Attribute
    end
<AttributeUsageAttribute(AttributeTargets.All)>
Public Class DefaultValueAttribute
	Inherits Attribute
NameDescription
System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a Boolean value.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using an 8-bit unsigned integer.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a Unicode character.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a double-precision floating point number.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a 16-bit signed integer.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a 32-bit signed integer.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a 64-bit signed integer.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a single-precision floating point number.

System_CAPS_pubmethod DefaultValueAttribute

Initializes a new instance of the DefaultValueAttribute class using a String.

System_CAPS_pubmethod DefaultValueAttribute

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.

NameDescription
System_CAPS_pubproperty

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

System_CAPS_pubproperty

Gets the default value of the property this attribute is bound to.

NameDescription
System_CAPS_pubmethod Equals

Returns whether the value of the given object is equal to the current DefaultValueAttribute.(Overrides AttributeEquals.)

System_CAPS_protmethod Finalize

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethod GetHashCode

Returns the hash code for this instance.(Overrides AttributeGetHashCode.)

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod 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.)

System_CAPS_pubmethod Match

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_protmethod MemberwiseClone

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethod SetValue

Sets the default value for the property to which this attribute is bound.

System_CAPS_pubmethod ToString

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetIDsOfNames

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfo

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfoCount

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeInvoke

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

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.

System_CAPS_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;
    }
 }

Private MyVar as Boolean = False
<DefaultValue(False)> _
Public Property MyProperty() As Boolean
    Get
        Return MyVar
    End Get
    Set
        MyVar = Value
    End Set 
End Property
private:
   bool myVal;

public:
   [DefaultValue(false)]
   property bool MyProperty 
   {
      bool get()
      {
         return myVal;
      }

      void set( bool value )
      {
         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());
' Gets the attributes for the property.
Dim attributes As AttributeCollection = _
    TypeDescriptor.GetProperties(Me)("MyProperty").Attributes

' Prints the default value by retrieving the DefaultValueAttribute
' from the AttributeCollection. 
Dim myAttribute As DefaultValueAttribute = _
    CType(attributes(GetType(DefaultValueAttribute)), DefaultValueAttribute)
Console.WriteLine(("The default value is: " & myAttribute.Value.ToString()))
// 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 = dynamic_cast<DefaultValueAttribute^>(attributes[ DefaultValueAttribute::typeid ]);
Console::WriteLine( "The default value is: {0}", myAttribute->Value );
Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

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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