ServiceKnownTypeAttribute 类

定义

命名空间:

System.ServiceModel

程序集:

System.ServiceModel.Primitives.dll

包:

System.ServiceModel.Primitives v8.0.0

Source:

ServiceKnownTypeAttribute.cs

指定序列化或反序列化时服务要使用的已知类型。

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

继承

Object

Attribute

ServiceKnownTypeAttribute

属性

AttributeUsageAttribute

示例

以下示例将 特性应用于接口， ServiceKnownTypeAttribute 其中 特性指定方法名称和声明类型。

// 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

或者，将该特性应用于指定要包含的已知类型的接口。

// 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

注解

ServiceKnownTypeAttribute适用于在创建 Windows Communication Foundation (WCF) 服务协定时使用， (接口定义服务及其方法) 。 已知类型是序列化或反序列化发生时对象图中可能存在的类型。 有关已知类型的详细信息，请参阅数据协定已知类型。

若要使用 MethodName 属性，请创建一个类，其中包含一个方法 (或返回类型数组的) ， (每种类型都是已知类型) 。 应用 特性时，将 methodName 设置为返回类型列表的方法的名称，并将 设置为 declaringType 包含该方法的类型。 方法必须返回实现 接口的类型 IEnumerable<T> 。 方法还必须包含 类型的 ICustomAttributeProvider参数。

您还可以将该属性多次用于接口、类或方法，每次指定一个新的已知类型。

注意

可以在 Microsoft Visual Basic 或 C# 代码中使用 单词ServiceKnownType，而不是较长ServiceKnownTypeAttribute的 。

构造函数

ServiceKnownTypeAttribute(String)	初始化 ServiceKnownTypeAttribute 类的新实例，并指定返回已知类型的方法的名称。
ServiceKnownTypeAttribute(String, Type)	使用返回已知类型的方法的名称，以及包含返回已知类型的方法的类型来初始化 ServiceKnownTypeAttribute 类的新实例。
ServiceKnownTypeAttribute(Type)	使用指定的已知类型初始化 ServiceKnownTypeAttribute 类的新实例。

属性

DeclaringType	获取包含返回已知类型的方法的类型。
MethodName	获取返回已知类型集合的方法的名称。
Type	可包含在对象图中的已知类型。
TypeId	在派生类中实现时，获取此 Attribute 的唯一标识符。 (继承自 Attribute)

方法

Equals(Object)	返回一个值，该值指示此实例是否与指定的对象相等。 (继承自 Attribute)
GetHashCode()	返回此实例的哈希代码。 (继承自 Attribute)
GetType()	获取当前实例的 Type。 (继承自 Object)
IsDefaultAttribute()	在派生类中重写时，指示此实例的值是否是派生类的默认值。 (继承自 Attribute)
Match(Object)	当在派生类中重写时，返回一个指示此实例是否等于指定对象的值。 (继承自 Attribute)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
ToString()	返回表示当前对象的字符串。 (继承自 Object)

另请参阅

• DataContractAttribute
• DataMemberAttribute
• 数据协定已知类型