ServiceKnownTypeAttribute Clase

Definición

public ref class ServiceKnownTypeAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Interface | System.AttributeTargets.Method, AllowMultiple=true, Inherited=true)]
public sealed class ServiceKnownTypeAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Interface | System.AttributeTargets.Method, AllowMultiple=true, Inherited=true)>]
type ServiceKnownTypeAttribute = class
    inherit Attribute

Public NotInheritable Class ServiceKnownTypeAttribute
Inherits Attribute

Herencia

Object

Attribute

ServiceKnownTypeAttribute

Atributos

AttributeUsageAttribute

Ejemplos

En el ejemplo siguiente se aplica el ServiceKnownTypeAttribute atributo a una interfaz donde el atributo especifica un nombre de método y un tipo declarativo.

// Define a service contract and apply the ServiceKnownTypeAttribute
// to specify types to include when generating client code.
// The types must have the DataContractAttribute and DataMemberAttribute
// applied to be serialized and deserialized. The attribute specifies the
// name of a method (GetKnownTypes) in a class (Helper) defined below.
[ServiceKnownType("GetKnownTypes", typeof(Helper))]
[ServiceContract()]
public interface ICatalog
{
    // Any object type can be inserted into a Hashtable. The
    // ServiceKnownTypeAttribute allows you to include those types
    // with the client code.
    [OperationContract]
    Hashtable GetItems();
}

// This class has the method named GetKnownTypes that returns a generic IEnumerable.
static class Helper
{
    public static IEnumerable<Type> GetKnownTypes(ICustomAttributeProvider provider)
    {
        System.Collections.Generic.List<System.Type> knownTypes =
            new System.Collections.Generic.List<System.Type>();
        // Add any types to include here.
        knownTypes.Add(typeof(Widget));
        knownTypes.Add(typeof(Machine));
        return knownTypes;
    }
}

[DataContract()]
public class Widget
{
    [DataMember]
    public string Id;
    [DataMember]
    public string Catalog;
}

[DataContract()]
public class Machine : Widget
{
    [DataMember]
    public string Maker;
}

' Define a service contract and apply the ServiceKnownTypeAttribute
' to specify types to include when generating client code. 
' The types must have the DataContractAttribute and DataMemberAttribute
' applied to be serialized and deserialized. The attribute specifies the 
' name of a method (GetKnownTypes) in a class (Helper) defined below.
<ServiceKnownType("GetKnownTypes", GetType(Helper)), ServiceContract()>  _
Public Interface ICalculator
    ' Any object type can be inserted into a Hashtable. The 
    ' ServiceKnownTypeAttribute allows you to include those types
    ' with the client code.
    <OperationContract()>  _
    Function GetItems() As Hashtable 
End Interface 

' This class has the method named GetKnownTypes that returns a generic IEnumerable.
Friend Class Helper
    Public Shared  Function GetKnownTypes(provider As ICustomAttributeProvider) _
     As IEnumerable(of Type) 
        Dim knownTypes As List(Of Type) = New List(Of Type)
        ' Add any types to include here.
        knownTypes.Add(GetType(Widget))
        knownTypes.Add(GetType(Machine))
        Return knownTypes
    End Function 
End Class 

<DataContract()>  _
Public Class Widget
    <DataMember()>  _
    Public Id As String
    <DataMember()>  _
    Public Catalog As String
End Class 

<DataContract()>  _
Public Class Machine
    Inherits Widget
    <DataMember()>  _
    Public Maker As String
End Class

Por otra parte, aplique el atributo a la interfaz especificando el tipo conocido que se vaya a incluir.

// Apply the ServiceKnownTypeAttribute to the
// interface specifying the type to include. Apply
// the attribute more than once if needed.
[ServiceKnownType(typeof(Widget))]
[ServiceKnownType(typeof(Machine))]
[ServiceContract()]
public interface ICatalog2
{
    // Any object type can be inserted into a Hashtable. The
    // ServiceKnownTypeAttribute allows you to include those types
    // with the client code.
    [OperationContract]
    Hashtable GetItems();
}

' Apply the ServiceKnownTypeAttribute to the 
' interface specifying the type to include. Apply the attribute
' more than once, if needed.
<ServiceKnownType(GetType(Widget)), ServiceKnownType(GetType(Machine)), _
 ServiceContract()>  _
Public Interface ICalculator2
    ' Any object type can be inserted into a Hashtable. The 
    ' ServiceKnownTypeAttribute allows you to include those types
    ' with the client code.
    <OperationContract()>  _
    Function GetItems() As Hashtable 
End Interface

Comentarios

ServiceKnownTypeAttribute está pensado para su uso al crear contratos de servicio de Windows Communication Foundation (WCF) (interfaces que definen el servicio y sus métodos). Los tipos conocidos son tipos que pueden estar presentes en un gráfico de objetos cuando se produce la serialización o deserialización. Para más información sobre los tipos conocidos, consulte Tipos conocidos de contratos de datos.

Para usar la MethodName propiedad , cree una clase que contenga un método (o métodos) que devuelva una matriz de tipos (cada uno de ellos es un tipo conocido). Al aplicar el atributo , establezca en methodName el nombre de un método que devuelva la lista de tipos y establezca en declaringType el tipo que contiene el método . El método debe devolver un tipo que implemente la IEnumerable<T> interfaz . El método también debe incluir un parámetro de tipo ICustomAttributeProvider.

También puede aplicar el atributo varias veces en una interfaz, clase o método. En cada caso se especificaría un nuevo tipo conocido.

Constructores

Propiedades

Métodos

Implementaciones de interfaz explícitas

Se aplica a

Consulte también

• DataContractAttribute
• DataMemberAttribute
• Tipos conocidos de contratos de datos