Specifies known types to be used by a service when serializing or deserializing.
Assembly: System.ServiceModel (in System.ServiceModel.dll)
Thetype exposes the following members.
|ServiceKnownTypeAttribute(String)||Initializes a new instance of the class and specifies the name of a method that returns the known types.|
|ServiceKnownTypeAttribute(Type)||Initializes a new instance of the class with the specified known type.|
|ServiceKnownTypeAttribute(String, Type)||Initializes a new instance of the class with the name of a method that returns the known types and the type that contains the method (or methods) that returns the known types.|
|DeclaringType||Gets the type that contains the methods that return the known types.|
|MethodName||Gets the name of a method that returns the collection of known types.|
|Type||The known type that can be included in an object graph.|
|TypeId||When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)|
|Equals||Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)|
|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. (Inherited from Attribute.)|
|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.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
|_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.)|
The is intended for use when creating service contracts (interfaces that define the service and its methods). The known types are types that may be present in an object graph when serialization or deserialization occurs. For more information about known types, see Data Contract Known Types.
To use the MethodName property, create a class that contains a method (or methods) that returns an array of types (each being a known type). When applying the attribute, set the methodName to the name of a method that returns the list of types and set the declaringType to the type that contains the method. The method must return a type that implements the IEnumerable(Of T) interface. The method must also include a parameter of type ICustomAttributeProvider.
You can also apply the attribute several times to an interface, class, or method, each time specifying a new known type.
You can use the word ServiceKnownType in your Microsoft Visual Basic or C# code instead of the longer ServiceKnownTypeAttribute.
The following example applies the attribute to an interface where the attribute specifies a method name and a declaring type.
' 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
Alternatively, apply the attribute to the interface specifying the known type to include.
' 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
Windows 7, Windows Vista SP1 or later, Windows XP SP3, 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.