<TypeParameter> Element (.NET Native)

Makale
10/20/2022

Applies policy to the type represented by a Type argument passed to a method.

Syntax

<Parameter Name="parameter_name"
           Activate="policy_type"
           Browse="policy_type"
           Dynamic="policy_type"
           Serialize="policy_type"
           DataContractSerializer="policy_type"
           DataContractJsonSerializer="policy_type"
           XmlSerializer="policy_type"
           MarshalObject="policy_type"
           MarshalDelegate="policy_type"
           MarshalStructure="policy_type" />

Attributes and Elements

The following sections describe attributes, child elements, and parent elements.

Attributes

Attribute	Attribute type	Description
`Name`	General	Required attribute. The name of the parameter of type Type. For example, for the method signature `Type.GetInterfaceMap(Type interfaceType)`, the value of the `Name` attribute is "interfaceType".
`Activate`	Reflection	Optional attribute. Controls runtime access to constructors to enable activation of instances.
`Browse`	Reflection	Optional attribute. Controls querying for information about program elements, but does not enable any runtime access.
`Dynamic`	Reflection	Optional attribute. Controls runtime access to all type members, including constructors, methods, fields, properties, and events, to enable dynamic programming.
`Serialize`	Serialization	Optional attribute. Controls runtime access to constructors, fields, and properties, to enable type instances to be serialized and deserialized by libraries such as the Newtonsoft JSON serializer.
`DataContractSerializer`	Serialization	Optional attribute. Controls policy for serialization that uses the System.Runtime.Serialization.DataContractSerializer class.
`DataContractJsonSerializer`	Serialization	Optional attribute. Controls policy for JSON serialization that uses the System.Runtime.Serialization.Json.DataContractJsonSerializer class.
`XmlSerializer`	Serialization	Optional attribute. Controls policy for XML serialization that uses the System.Xml.Serialization.XmlSerializer class.
`MarshalObject`	Interop	Optional attribute. Controls policy for marshaling reference types to Windows Runtime and COM.
`MarshalDelegate`	Interop	Optional attribute. Controls policy for marshaling delegate types as function pointers to native code.
`MarshalStructure`	Interop	Optional attribute. Controls policy for marshaling value types to native code.

Name attribute

Value	Description
parameter_name	The name of the parameter of type Type. For example, for the method signature `Type.GetInterfaceMap(Type interfaceType)`, the value of the `Name` attribute is "interfaceType".

All other attributes

Value	Description
policy_setting	The setting to apply to this policy type. Possible values are `All`, `Public`, `PublicAndInternal`, `Required Public`, `Required PublicAndInternal`, and `Required All`. For more information, see Runtime Directive Policy Settings.

Child Elements

None.

Parent Elements

Element	Description
<Method>	Applies runtime reflection policy to a constructor or method.

Remarks

The <TypeParameter> element is similar to the <Parameter> element, except that it can be applied only to parameters of type Type. It applies policy to whatever type is represented at run time by the type argument specified by the Name attribute.

For example, the NewtonSoft JSON serializer includes a static JsonConvert.DeserializeObject(String value, Type type) method. The following reflection directives:

<Directives xmlns="http://schemas.microsoft.com/netfx/2013/01/metadata">
   <Type Name="Newtonsoft.Json.JsonConvert" >
      <Method Name="DeserializeObject">
         <GenericParameter Name="type" Serialize="Required All" />
      </Method>
   </Type>
</Directives>

specify that metadata for the runtime type represented by the type argument should be made available for serialization. If these runtime directives apply to a project that includes the following source code:

Type t = typeof(StockQuote);
Object obj = JsonConvert.DeserializeObject(data, t);

the reflection directives make metadata for the StockQuote type available for the NewtonSoft JSON serializer at run time.

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