ServiceKnownTypeAttribute Class
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ServiceKnownTypeAttribute Class

 

Specifies known types to be used by a service when serializing or deserializing.

Namespace:   System.ServiceModel
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

System.Object
  System.Attribute
    System.ServiceModel.ServiceKnownTypeAttribute

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

NameDescription
System_CAPS_pubmethodServiceKnownTypeAttribute(String)

Initializes a new instance of the ServiceKnownTypeAttribute class and specifies the name of a method that returns the known types.

System_CAPS_pubmethodServiceKnownTypeAttribute(String, Type)

Initializes a new instance of the ServiceKnownTypeAttribute 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.

System_CAPS_pubmethodServiceKnownTypeAttribute(Type)

Initializes a new instance of the ServiceKnownTypeAttribute class with the specified known type.

NameDescription
System_CAPS_pubpropertyDeclaringType

Gets the type that contains the methods that return the known types.

System_CAPS_pubpropertyMethodName

Gets the name of a method that returns the collection of known types.

System_CAPS_pubpropertyType

The known type that can be included in an object graph.

System_CAPS_pubpropertyTypeId

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

NameDescription
System_CAPS_pubmethodEquals(Object)

This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)

System_CAPS_pubmethodGetHashCode()

Returns the hash code for this instance.(Inherited from Attribute.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodIsDefaultAttribute()

When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)

System_CAPS_pubmethodMatch(Object)

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfoCount(UInt32)

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

The ServiceKnownTypeAttribute is intended for use when creating Windows Communication Foundation (WCF) 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<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.

System_CAPS_noteNote

You can use the word ServiceKnownType in your Microsoft Visual Basic or C# code instead of the longer ServiceKnownTypeAttribute.

The following example applies the ServiceKnownTypeAttribute 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", 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;
}

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(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();
}

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 3.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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