DefaultValueAttribute Class
Specifies the default value for a property.
Assembly: System (in System.dll)
The DefaultValueAttribute type exposes the following members.
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | DefaultValueAttribute(Boolean) | Initializes a new instance of the DefaultValueAttribute class using a Boolean value. |
![]() ![]() ![]() | DefaultValueAttribute(Byte) | Initializes a new instance of the DefaultValueAttribute class using an 8-bit unsigned integer. |
![]() ![]() ![]() | DefaultValueAttribute(Char) | Initializes a new instance of the DefaultValueAttribute class using a Unicode character. |
![]() ![]() ![]() | DefaultValueAttribute(Double) | Initializes a new instance of the DefaultValueAttribute class using a double-precision floating point number. |
![]() ![]() ![]() | DefaultValueAttribute(Int16) | Initializes a new instance of the DefaultValueAttribute class using a 16-bit signed integer. |
![]() ![]() ![]() | DefaultValueAttribute(Int32) | Initializes a new instance of the DefaultValueAttribute class using a 32-bit signed integer. |
![]() ![]() ![]() | DefaultValueAttribute(Int64) | Initializes a new instance of the DefaultValueAttribute class using a 64-bit signed integer. |
![]() ![]() ![]() | DefaultValueAttribute(Object) | Initializes a new instance of the DefaultValueAttribute class. |
![]() ![]() ![]() | DefaultValueAttribute(Single) | Initializes a new instance of the DefaultValueAttribute class using a single-precision floating point number. |
![]() ![]() ![]() | DefaultValueAttribute(String) | Initializes a new instance of the DefaultValueAttribute class using a String. |
![]() | DefaultValueAttribute(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. |
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | Equals | Returns whether the value of the given object is equal to the current DefaultValueAttribute. (Overrides Attribute::Equals(Object).) |
![]() ![]() ![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() ![]() ![]() | GetHashCode | Returns the hash code for this instance. (Overrides Attribute::GetHashCode().) |
![]() ![]() ![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | 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.) |
![]() ![]() | Match | When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.) |
![]() ![]() ![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | SetValue | Sets the default value for the property to which this attribute is bound. |
![]() ![]() ![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
![]() ![]() | _Attribute::GetIDsOfNames | Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.) |
![]() ![]() | _Attribute::GetTypeInfo | Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.) |
![]() ![]() | _Attribute::GetTypeInfoCount | Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.) |
![]() ![]() | _Attribute::Invoke | 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.
Note |
|---|
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.
| Topic | Location |
|---|---|
| Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Walkthrough: Developing and Using a Custom Server Control | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Walkthrough: Developing and Using a Custom Server Control | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1 | Authoring ASP.NET Controls |
The following example sets the default value of MyProperty to false.
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 = dynamic_cast<DefaultValueAttribute^>(attributes[ DefaultValueAttribute::typeid ]); Console::WriteLine( "The default value is: {0}", myAttribute->Value );
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

