.NET Framework Class Library
ReturnValueNameAttribute Class

Specifies the name of the return value of a method in a Windows Runtime component.

Inheritance Hierarchy
SystemObject
   SystemAttribute
    System.Runtime.InteropServices.WindowsRuntimeReturnValueNameAttribute

Namespace:   System.Runtime.InteropServices.WindowsRuntime
Assemblies:   System.Runtime.InteropServices.WindowsRuntime (in System.Runtime.InteropServices.WindowsRuntime.dll)
  mscorlib (in mscorlib.dll)
Syntax
<[%$TOPIC/hh973181_en-us_VS_110_2_0_0_0_0%]([%$TOPIC/hh973181_en-us_VS_110_2_0_0_0_1%].Delegate Or [%$TOPIC/hh973181_en-us_VS_110_2_0_0_0_2%].ReturnValue, AllowMultiple := False,  _
	Inherited := False)> _
Public NotInheritable Class ReturnValueNameAttribute _
	Inherits [%$TOPIC/hh973181_en-us_VS_110_2_0_0_0_3%]
[[%$TOPIC/hh973181_en-us_VS_110_2_0_1_0_0%]([%$TOPIC/hh973181_en-us_VS_110_2_0_1_0_1%].Delegate|[%$TOPIC/hh973181_en-us_VS_110_2_0_1_0_2%].ReturnValue, AllowMultiple = false, 
	Inherited = false)]
public sealed class ReturnValueNameAttribute : [%$TOPIC/hh973181_en-us_VS_110_2_0_1_0_3%]
[[%$TOPIC/hh973181_en-us_VS_110_2_0_2_0_0%]([%$TOPIC/hh973181_en-us_VS_110_2_0_2_0_1%]::Delegate|[%$TOPIC/hh973181_en-us_VS_110_2_0_2_0_2%]::ReturnValue, AllowMultiple = false, 
	Inherited = false)]
public ref class ReturnValueNameAttribute sealed : public [%$TOPIC/hh973181_en-us_VS_110_2_0_2_0_3%]
[<[%$TOPIC/hh973181_en-us_VS_110_2_0_3_0_0%]>]
[<[%$TOPIC/hh973181_en-us_VS_110_2_0_3_0_1%]([%$TOPIC/hh973181_en-us_VS_110_2_0_3_0_2%].Delegate|[%$TOPIC/hh973181_en-us_VS_110_2_0_3_0_3%].ReturnValue, AllowMultiple = false, 
    Inherited = false)>]
type ReturnValueNameAttribute =  
    class 
        inherit [%$TOPIC/hh973181_en-us_VS_110_2_0_3_0_4%] 
    end
public final class ReturnValueNameAttribute extends [%$TOPIC/hh973181_en-us_VS_110_2_0_4_0_0%]

The ReturnValueNameAttribute type exposes the following members.

Constructors
  NameDescription
Public method ReturnValueNameAttributeInitializes a new instance of the ReturnValueNameAttribute class, and specifies the name of the return value.
Top
Properties
  NameDescription
Public property NameGets the name that was specified for the return value of a method in a Windows Runtime component.
Public property TypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Top
Methods
  NameDescription
Public method EqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public method GetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method MatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
Top
Explicit Interface Implementations
  NameDescription
Explicit interface implemetation Private method _AttributeGetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeInvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
Top
Remarks

In a Windows Runtime component, all the parameters of a method and the return value must have names. By default, Winmdexp.exe (Windows Runtime Metadata Export Tool) gives the return value the name "value". When you use a component in a Windows Store app written in JavaScript, you can use this name to retrieve the return value. For example, suppose a component defines a method that has a return value and two out parameters (ByRef parameters with the OutAttribute attribute in Visual Basic):

public static int ComputeAverage([ReadOnlyArray()] int[] input,
    out int minValue, out int maxValue)
{
    …
}
Public Shared Function ComputeAverage( _
        <ReadOnlyArray()> ByVal input As Integer, _
        <Out()> ByRef minValue As Integer, _
        <Out()> ByRef maxValue As Integer) As Integer
    …
End Function

When you call the function from JavaScript, you can access the return value by its default name (value):

    var data = [5, 13, 23, 37];
    var results = SampleComponent.TestStuff.computeAverage(data);
    var formattedResults = "Min=" + results.minValue + ", Avg=" + 
        results.value + ", Max=" + results.maxValue;

You must give the return value a different name if you already have a parameter named "value". Or you might simply want to use a more meaningful name (such as "average" in this example). Apply the ReturnValueNameAttribute attribute to your method and specify a new name.

[return: ReturnValueName("average")]
public static int ComputeAverage([ReadOnlyArray()] int[] input,
    out int minValue, out int maxValue)
{
    …
}
Public Shared Function ComputeAverage( _
        <ReadOnlyArray()> ByVal input As Integer, _
        <Out()> ByRef minValue As Integer, _
        <Out()> ByRef maxValue As Integer) _
            As <ReturnValueName("average")> Integer
    …
End Function
Version Information

.NET Framework

Supported in: 4.6, 4.5

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.