InstanceDescriptor Class
Provides the information necessary to create an instance of an object. This class cannot be inherited.
Assembly: System (in System.dll)
| Name | Description | |
|---|---|---|
![]() | InstanceDescriptor(MemberInfo^, ICollection^) | Initializes a new instance of the InstanceDescriptor class using the specified member information and arguments. |
![]() | InstanceDescriptor(MemberInfo^, ICollection^, Boolean) | Initializes a new instance of the InstanceDescriptor class using the specified member information, arguments, and value indicating whether the specified information completely describes the instance. |
| Name | Description | |
|---|---|---|
![]() | Arguments | Gets the collection of arguments that can be used to reconstruct an instance of the object that this instance descriptor represents. |
![]() | IsComplete | Gets a value indicating whether the contents of this InstanceDescriptor completely identify the instance. |
![]() | MemberInfo | Gets the member information that describes the instance this descriptor is associated with. |
| Name | Description | |
|---|---|---|
![]() | Equals(Object^) | Determines whether the specified object is equal to the current object.(Inherited from Object.) |
![]() | GetHashCode() | Serves as the default hash function. (Inherited from Object.) |
![]() | GetType() | |
![]() | Invoke() | Invokes this instance descriptor and returns the object the descriptor describes. |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
InstanceDescriptor can store information that describes an instance of an object. This information can be used to create an instance of the object.
Some custom serializers use InstanceDescriptor to represent serializable objects. Several methods of a TypeDescriptor use InstanceDescriptor to represent or instantiate objects.
An InstanceDescriptor provides the following members:
A MemberInfo property that describes this object.
An Arguments property that consists of the constructor arguments that can be used to instantiate this object.
A Boolean IsComplete property that indicates whether the object is completely represented by the current information.
An Invoke method that can be used to create an instance of the represented object.
The following code example illustrates how to use a type converter that participates in code generation through the use of instance descriptors.
#using <system.dll> #using <system.drawing.dll> using namespace System; using namespace System::ComponentModel; using namespace System::ComponentModel::Design::Serialization; using namespace System::Drawing; using namespace System::Globalization; using namespace System::Collections; using namespace System::Reflection; /* This sample shows how to support code generation for a custom type of object using a type converter and InstanceDescriptor objects. To use this code, copy it to a file and add the file to a project. Then add a component to the project and declare a Triangle field and a public property with accessors for the Triangle field on the component. The Triangle property will be persisted using code generation. */ ref class TriangleConverter; [TypeConverter(TriangleConverter::typeid)] public ref class Triangle { private: // Triangle members Point P1; Point P2; Point P3; public: property Point Point1 { Point get() { return P1; } void set( Point value ) { P1 = value; } } property Point Point2 { Point get() { return P2; } void set( Point value ) { P2 = value; } } property Point Point3 { Point get() { return P3; } void set( Point value ) { P3 = value; } } Triangle( Point point1, Point point2, Point point3 ) { P1 = point1; P2 = point2; P3 = point3; } /* A TypeConverter for the Triangle object. Note that you can make it internal, private, or any scope you want and the designers will still be able to use it through the TypeDescriptor object. This type converter provides the capability to convert to an InstanceDescriptor. This object can be used by the .NET Framework to generate source code that creates an instance of a Triangle object. */ [System::Security::Permissions::PermissionSet(System::Security:: Permissions::SecurityAction::Demand, Name = "FullTrust")] ref class TriangleConverter: public TypeConverter { public: /* This method overrides CanConvertTo from TypeConverter. This is called when someone wants to convert an instance of Triangle to another type. Here, only conversion to an InstanceDescriptor is supported. */ virtual bool CanConvertTo( ITypeDescriptorContext^ context, Type^ destinationType ) override { if ( destinationType == InstanceDescriptor::typeid ) { return true; } // Always call the base to see if it can perform the conversion. return TypeConverter::CanConvertTo( context, destinationType ); } /* This code performs the actual conversion from a Triangle to an InstanceDescriptor. */ virtual Object^ ConvertTo( ITypeDescriptorContext^ context, CultureInfo^ culture, Object^ value, Type^ destinationType ) override { if ( destinationType == InstanceDescriptor::typeid ) { array<Type^>^type1 = {Point::typeid,Point::typeid,Point::typeid}; ConstructorInfo^ ci = Triangle::typeid->GetConstructor( type1 ); Triangle^ t = safe_cast<Triangle^>(value); array<Object^>^obj1 = {t->Point1,t->Point2,t->Point3}; return gcnew InstanceDescriptor( ci,safe_cast<ICollection^>(obj1) ); } // Always call base, even if you can't convert. return TypeConverter::ConvertTo( context, culture, value, destinationType ); } }; }; public ref class TestComponent: public System::ComponentModel::Component { private: Triangle^ myTriangle; public: TestComponent() { myTriangle = gcnew Triangle( Point(5,5),Point(10,10),Point(1,8) ); } property Triangle^ MyTriangle { Triangle^ get() { return myTriangle; } void set( Triangle^ value ) { myTriangle = value; } } };
Available since 1.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

