CustomAttributeTypedArgument Struktur

Definition

public value class CustomAttributeTypedArgument

public value class CustomAttributeTypedArgument : IEquatable<System::Reflection::CustomAttributeTypedArgument>

public struct CustomAttributeTypedArgument

public readonly struct CustomAttributeTypedArgument

public readonly struct CustomAttributeTypedArgument : IEquatable<System.Reflection.CustomAttributeTypedArgument>

[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public struct CustomAttributeTypedArgument

type CustomAttributeTypedArgument = struct

[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Serializable>]
type CustomAttributeTypedArgument = struct

Public Structure CustomAttributeTypedArgument

Public Structure CustomAttributeTypedArgument
Implements IEquatable(Of CustomAttributeTypedArgument)

Vererbung

Object

ValueType

CustomAttributeTypedArgument

Attribute

ComVisibleAttribute SerializableAttribute

Implementiert

IEquatable<CustomAttributeTypedArgument>

Beispiele

Im folgenden Beispiel wird ein benutzerdefiniertes Attribut mit vier Konstruktoren und vier Eigenschaften definiert. Zwei der Eigenschaften sind schreibgeschützt und werden mithilfe der Positionsparameter der Konstruktoren festgelegt. Die anderen beiden Eigenschaften sind Lese-/Schreibzugriff und können nur mithilfe von benannten Argumenten festgelegt werden. Eine positionale Eigenschaft ist ein Array von Zeichenfolgen, und eine benannte Eigenschaft ist ein Array von ganzen Zahlen.

Das Attribut wird auf die Assembly, auf einen in der Assembly deklarierten Typ, auf eine Methode des Typs und auf einen Parameter der Methode angewendet. Für diese Fälle werden unterschiedliche Konstruktoren verwendet. Wenn die Assembly ausgeführt wird, lädt sich die Assembly in den reinen Spiegelungskontext und zeigt die benutzerdefinierten Attribute an.

Das Attribut, das auf den Typ angewendet wird, veranschaulicht Arrayeigenschaften mit positionsbezogenen und benannten Argumenten.

using namespace System;
using namespace System::Reflection;
using namespace System::Collections::Generic;
using namespace System::Collections::ObjectModel;

// An enumeration used by the ExampleAttribute class.
public enum class ExampleKind
{
   FirstKind, SecondKind, ThirdKind, FourthKind
};

// An example attribute. The attribute can be applied to all
// targets, from assemblies to parameters.
//
[AttributeUsage(AttributeTargets::All)]
public ref class ExampleAttribute: public Attribute
{
private:
   // Data for properties.
   ExampleKind kindValue;
   String^ noteValue;
   array<String^>^ arrayStrings;
   array<int>^ arrayNumbers;

   // Constructors. 
   void ExampleAttributeInitialize( ExampleKind initKind, array<String^>^ initStrings )
   {
      kindValue = initKind;
      arrayStrings = initStrings;
   }
public:
   ExampleAttribute()
   {
      ExampleAttributeInitialize( ExampleKind::FirstKind, nullptr );
   }
   ExampleAttribute( ExampleKind initKind )
   {
      ExampleAttributeInitialize( initKind, nullptr );
   }
   ExampleAttribute( ExampleKind initKind, array<String^>^ initStrings )
   {
      ExampleAttributeInitialize( initKind, initStrings );
   }

   // Properties. The Note and Numbers properties must be read/write, so they
   // can be used as named parameters.
   //
   property ExampleKind Kind 
   {
      ExampleKind get()
      {
         return kindValue;
      }
   }
   property array<String^>^ Strings
   {
      array<String^>^ get()
      {
         return arrayStrings;
      }
   }
   property String^ Note 
   {
      String^ get()
      {
         return noteValue;
      }

      void set( String^ value )
      {
         noteValue = value;
      }
   }
   property array<int>^ Numbers
   {
      array<int>^ get()
      {
         return arrayNumbers;
      }

      void set( array<int>^ value )
      {
         arrayNumbers = value;
      }
   }
};

// The example attribute is applied to the assembly.
[assembly:Example(ExampleKind::ThirdKind,Note="This is a note on the assembly.")];

// The example attribute is applied to the test class.
//
[Example(ExampleKind::SecondKind, 
         gcnew array<String^> { "String array argument, line 1", 
                        "String array argument, line 2", 
                        "String array argument, line 3" }, 
         Note="This is a note on the class.",
         Numbers = gcnew array<int> { 53, 57, 59 })] 
public ref class Test
{
public:
   // The example attribute is applied to a method, using the
   // parameterless constructor and supplying a named argument.
   // The attribute is also applied to the method parameter.
   //
   [Example(Note="This is a note on a method.")]
   void TestMethod( [Example] Object^ arg ){}

   // Main() gets objects representing the assembly, the test
   // type, the test method, and the method parameter. Custom
   // attribute data is displayed for each of these.
   //
   static void Main()
   {
      Assembly^ assembly = Assembly::ReflectionOnlyLoad( "Source" );
      Type^ t = assembly->GetType( "Test" );
      MethodInfo^ m = t->GetMethod( "TestMethod" );
      array<ParameterInfo^>^p = m->GetParameters();

      Console::WriteLine( "\r\nAttributes for assembly: '{0}'", assembly );
      ShowAttributeData( CustomAttributeData::GetCustomAttributes( assembly ) );
      Console::WriteLine( "\r\nAttributes for type: '{0}'", t );
      ShowAttributeData( CustomAttributeData::GetCustomAttributes( t ) );
      Console::WriteLine( "\r\nAttributes for member: '{0}'", m );
      ShowAttributeData( CustomAttributeData::GetCustomAttributes( m ) );
      Console::WriteLine( "\r\nAttributes for parameter: '{0}'", p );
      ShowAttributeData( CustomAttributeData::GetCustomAttributes( p[ 0 ] ) );
   }

private:
    static void ShowValueOrArray(CustomAttributeTypedArgument^ cata)
    {
        if (cata->Value->GetType() == ReadOnlyCollection<CustomAttributeTypedArgument>::typeid)
        {
            Console::WriteLine("         Array of '{0}':", cata->ArgumentType);

            for each (CustomAttributeTypedArgument^ cataElement in 
                (ReadOnlyCollection<CustomAttributeTypedArgument>^) cata->Value)
            {
                Console::WriteLine("             Type: '{0}'  Value: '{1}'",
                    cataElement->ArgumentType, cataElement->Value);
            }
        }
        else
        {
            Console::WriteLine( "         Type: '{0}'  Value: '{1}'",
               cata->ArgumentType, cata->Value );
        }
    }

   static void ShowAttributeData( IList< CustomAttributeData^ >^ attributes )
   {
      for each ( CustomAttributeData^ cad in attributes )
      {
         Console::WriteLine( "   {0}", cad );
         Console::WriteLine( "      Constructor: '{0}'", cad->Constructor );

         Console::WriteLine( "      Constructor arguments:" );
         for each ( CustomAttributeTypedArgument^ cata in cad->ConstructorArguments )
         {
            ShowValueOrArray(cata);
         }

         Console::WriteLine( "      Named arguments:" );
         for each ( CustomAttributeNamedArgument cana in cad->NamedArguments )
         {
            Console::WriteLine( "         MemberInfo: '{0}'", cana.MemberInfo );
            ShowValueOrArray(cana.TypedValue);
         }
      }
   }
};

int main()
{
   Test::Main();
}

/* This code example produces output similar to the following:

Attributes for assembly: 'source, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'
   [System.Runtime.CompilerServices.CompilationRelaxationsAttribute((Int32)8)]
      Constructor: 'Void .ctor(Int32)'
      Constructor arguments:
         Type: 'System.Int32'  Value: '8'
      Named arguments:
   [System.Runtime.CompilerServices.RuntimeCompatibilityAttribute(WrapNonExceptionThrows = True)]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
         MemberInfo: 'Boolean WrapNonExceptionThrows'
         Type: 'System.Boolean'  Value: 'True'
   [ExampleAttribute((ExampleKind)2, Note = "This is a note on the assembly.")]
      Constructor: 'Void .ctor(ExampleKind)'
      Constructor arguments:
         Type: 'ExampleKind'  Value: '2'
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on the assembly.'

Attributes for type: 'Test'
   [ExampleAttribute((ExampleKind)1, new String[3] { "String array argument, line 1", "String array argument, line 2", "String array argument, line 3" }, Note = "This is a note on the class.", Numbers = new Int32[3] { 53, 57, 59 })]
      Constructor: 'Void .ctor(ExampleKind, System.String[])'
      Constructor arguments:
         Type: 'ExampleKind'  Value: '1'
         Array of 'System.String[]':
             Type: 'System.String'  Value: 'String array argument, line 1'
             Type: 'System.String'  Value: 'String array argument, line 2'
             Type: 'System.String'  Value: 'String array argument, line 3'
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on the class.'
         MemberInfo: 'Int32[] Numbers'
         Array of 'System.Int32[]':
             Type: 'System.Int32'  Value: '53'
             Type: 'System.Int32'  Value: '57'
             Type: 'System.Int32'  Value: '59'

Attributes for member: 'Void TestMethod(System.Object)'
   [ExampleAttribute(Note = "This is a note on a method.")]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on a method.'

Attributes for parameter: 'System.Object arg'
   [ExampleAttribute()]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
*/

using System;
using System.Reflection;
using System.Collections.Generic;
using System.Collections.ObjectModel;

// The example attribute is applied to the assembly.
[assembly:Example(ExampleKind.ThirdKind, Note="This is a note on the assembly.")]

// An enumeration used by the ExampleAttribute class.
public enum ExampleKind
{
    FirstKind,
    SecondKind,
    ThirdKind,
    FourthKind
};

// An example attribute. The attribute can be applied to all
// targets, from assemblies to parameters.
//
[AttributeUsage(AttributeTargets.All)]
public class ExampleAttribute : Attribute
{
    // Data for properties.
    private ExampleKind kindValue;
    private string noteValue;
    private string[] arrayStrings;
    private int[] arrayNumbers;

    // Constructors. The parameterless constructor (.ctor) calls
    // the constructor that specifies ExampleKind and an array of
    // strings, and supplies the default values.
    //
    public ExampleAttribute(ExampleKind initKind, string[] initStrings)
    {
        kindValue = initKind;
        arrayStrings = initStrings;
    }
    public ExampleAttribute(ExampleKind initKind) : this(initKind, null) {}
    public ExampleAttribute() : this(ExampleKind.FirstKind, null) {}

    // Properties. The Note and Numbers properties must be read/write, so they
    // can be used as named parameters.
    //
    public ExampleKind Kind { get { return kindValue; }}
    public string[] Strings { get { return arrayStrings; }}
    public string Note
    {
        get { return noteValue; }
        set { noteValue = value; }
    }
    public int[] Numbers
    {
        get { return arrayNumbers; }
        set { arrayNumbers = value; }
    }
}

// The example attribute is applied to the test class.
//
[Example(ExampleKind.SecondKind,
         new string[] { "String array argument, line 1",
                        "String array argument, line 2",
                        "String array argument, line 3" },
         Note="This is a note on the class.",
         Numbers = new int[] { 53, 57, 59 })]
public class Test
{
    // The example attribute is applied to a method, using the
    // parameterless constructor and supplying a named argument.
    // The attribute is also applied to the method parameter.
    //
    [Example(Note="This is a note on a method.")]
    public void TestMethod([Example] object arg) { }

    // Main() gets objects representing the assembly, the test
    // type, the test method, and the method parameter. Custom
    // attribute data is displayed for each of these.
    //
    public static void Main()
    {
        Assembly asm = Assembly.ReflectionOnlyLoad("Source");
        Type t = asm.GetType("Test");
        MethodInfo m = t.GetMethod("TestMethod");
        ParameterInfo[] p = m.GetParameters();

        Console.WriteLine("\r\nAttributes for assembly: '{0}'", asm);
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(asm));
        Console.WriteLine("\r\nAttributes for type: '{0}'", t);
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(t));
        Console.WriteLine("\r\nAttributes for member: '{0}'", m);
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(m));
        Console.WriteLine("\r\nAttributes for parameter: '{0}'", p);
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(p[0]));
    }

    private static void ShowAttributeData(
        IList<CustomAttributeData> attributes)
    {
        foreach( CustomAttributeData cad in attributes )
        {
            Console.WriteLine("   {0}", cad);
            Console.WriteLine("      Constructor: '{0}'", cad.Constructor);

            Console.WriteLine("      Constructor arguments:");
            foreach( CustomAttributeTypedArgument cata
                in cad.ConstructorArguments )
            {
                ShowValueOrArray(cata);
            }

            Console.WriteLine("      Named arguments:");
            foreach( CustomAttributeNamedArgument cana
                in cad.NamedArguments )
            {
                Console.WriteLine("         MemberInfo: '{0}'",
                    cana.MemberInfo);
                ShowValueOrArray(cana.TypedValue);
            }
        }
    }

    private static void ShowValueOrArray(CustomAttributeTypedArgument cata)
    {
        if (cata.Value.GetType() == typeof(ReadOnlyCollection<CustomAttributeTypedArgument>))
        {
            Console.WriteLine("         Array of '{0}':", cata.ArgumentType);

            foreach (CustomAttributeTypedArgument cataElement in
                (ReadOnlyCollection<CustomAttributeTypedArgument>) cata.Value)
            {
                Console.WriteLine("             Type: '{0}'  Value: '{1}'",
                    cataElement.ArgumentType, cataElement.Value);
            }
        }
        else
        {
            Console.WriteLine("         Type: '{0}'  Value: '{1}'",
                cata.ArgumentType, cata.Value);
        }
    }
}

/* This code example produces output similar to the following:

Attributes for assembly: 'source, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'
   [System.Runtime.CompilerServices.CompilationRelaxationsAttribute((Int32)8)]
      Constructor: 'Void .ctor(Int32)'
      Constructor arguments:
         Type: 'System.Int32'  Value: '8'
      Named arguments:
   [System.Runtime.CompilerServices.RuntimeCompatibilityAttribute(WrapNonExceptionThrows = True)]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
         MemberInfo: 'Boolean WrapNonExceptionThrows'
         Type: 'System.Boolean'  Value: 'True'
   [ExampleAttribute((ExampleKind)2, Note = "This is a note on the assembly.")]
      Constructor: 'Void .ctor(ExampleKind)'
      Constructor arguments:
         Type: 'ExampleKind'  Value: '2'
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on the assembly.'

Attributes for type: 'Test'
   [ExampleAttribute((ExampleKind)1, new String[3] { "String array argument, line 1", "String array argument, line 2", "String array argument, line 3" }, Note = "This is a note on the class.", Numbers = new Int32[3] { 53, 57, 59 })]
      Constructor: 'Void .ctor(ExampleKind, System.String[])'
      Constructor arguments:
         Type: 'ExampleKind'  Value: '1'
         Array of 'System.String[]':
             Type: 'System.String'  Value: 'String array argument, line 1'
             Type: 'System.String'  Value: 'String array argument, line 2'
             Type: 'System.String'  Value: 'String array argument, line 3'
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on the class.'
         MemberInfo: 'Int32[] Numbers'
         Array of 'System.Int32[]':
             Type: 'System.Int32'  Value: '53'
             Type: 'System.Int32'  Value: '57'
             Type: 'System.Int32'  Value: '59'

Attributes for member: 'Void TestMethod(System.Object)'
   [ExampleAttribute(Note = "This is a note on a method.")]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
         MemberInfo: 'System.String Note'
         Type: 'System.String'  Value: 'This is a note on a method.'

Attributes for parameter: 'System.Object arg'
   [ExampleAttribute()]
      Constructor: 'Void .ctor()'
      Constructor arguments:
      Named arguments:
*/

Imports System.Reflection
Imports System.Collections.Generic
Imports System.Collections.ObjectModel

' The example attribute is applied to the assembly.
<Assembly:Example(ExampleKind.ThirdKind, Note:="This is a note on the assembly.")>

' An enumeration used by the ExampleAttribute class.
Public Enum ExampleKind
    FirstKind
    SecondKind
    ThirdKind
    FourthKind
End Enum

' An example attribute. The attribute can be applied to all
' targets, from assemblies to parameters.
'
<AttributeUsage(AttributeTargets.All)> _
Public Class ExampleAttribute
    Inherits Attribute

    ' Data for properties.
    Private kindValue As ExampleKind
    Private noteValue As String
    Private arrayStrings() As String
    Private arrayNumbers() As Integer

    ' Constructors. The parameterless constructor (.ctor) calls
    ' the constructor that specifies ExampleKind and an array of
    ' strings, and supplies the default values.
    '
    Public Sub New(ByVal initKind As ExampleKind, ByVal initStrings() As String)
        kindValue = initKind
        arrayStrings = initStrings
    End Sub
    Public Sub New(ByVal initKind As ExampleKind)
        Me.New(initKind, Nothing)
    End Sub
    Public Sub New()
        Me.New(ExampleKind.FirstKind, Nothing)
    End Sub

    ' Properties. The Note and Numbers properties must be read/write, so they 
    ' can be used as named parameters.
    '
    Public ReadOnly Property Kind As ExampleKind
        Get
            Return kindValue 
        End Get
    End Property
    Public ReadOnly Property Strings As String()
        Get
            Return arrayStrings 
        End Get
    End Property
    Public Property Note As String
        Get
            Return noteValue 
        End Get
        Set
            noteValue = value
        End Set
    End Property
    Public Property Numbers As Integer()
        Get
            Return arrayNumbers 
        End Get
        Set
            arrayNumbers = value
        End Set
    End Property
End Class

' The example attribute is applied to the test class.
'
<Example(ExampleKind.SecondKind, _
         New String() { "String array argument, line 1", _
                        "String array argument, line 2", _
                        "String array argument, line 3" }, _
         Note := "This is a note on the class.", _
         Numbers := New Integer() { 53, 57, 59 })> _
Public Class Test
    ' The example attribute is applied to a method, using the
    ' parameterless constructor and supplying a named argument.
    ' The attribute is also applied to the method parameter.
    '
    <Example(Note:="This is a note on a method.")> _
    Public Sub TestMethod(<Example()> ByVal arg As Object)
    End Sub

    ' Sub Main gets objects representing the assembly, the test
    ' type, the test method, and the method parameter. Custom
    ' attribute data is displayed for each of these.
    '
    Public Shared Sub Main()
        Dim asm As [Assembly] = Assembly.ReflectionOnlyLoad("source")
        Dim t As Type = asm.GetType("Test")
        Dim m As MethodInfo = t.GetMethod("TestMethod")
        Dim p() As ParameterInfo = m.GetParameters()

        Console.WriteLine(vbCrLf & "Attributes for assembly: '{0}'", asm)
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(asm))
        Console.WriteLine(vbCrLf & "Attributes for type: '{0}'", t)
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(t))
        Console.WriteLine(vbCrLf & "Attributes for member: '{0}'", m)
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(m))
        Console.WriteLine(vbCrLf & "Attributes for parameter: '{0}'", p)
        ShowAttributeData(CustomAttributeData.GetCustomAttributes(p(0)))
    End Sub

    Private Shared Sub ShowAttributeData( _
        ByVal attributes As IList(Of CustomAttributeData))

        For Each cad As CustomAttributeData _
            In CType(attributes, IEnumerable(Of CustomAttributeData))

            Console.WriteLine("   {0}", cad)
            Console.WriteLine("      Constructor: '{0}'", cad.Constructor)

            Console.WriteLine("      Constructor arguments:")
            For Each cata As CustomAttributeTypedArgument _
                In CType(cad.ConstructorArguments, IEnumerable(Of CustomAttributeTypedArgument))

                ShowValueOrArray(cata)
            Next

            Console.WriteLine("      Named arguments:")
            For Each cana As CustomAttributeNamedArgument _
                In CType(cad.NamedArguments, IEnumerable(Of CustomAttributeNamedArgument))

                Console.WriteLine("         MemberInfo: '{0}'", _
                    cana.MemberInfo)
                ShowValueOrArray(cana.TypedValue)
            Next
        Next
    End Sub

    Private Shared Sub ShowValueOrArray(ByVal cata As CustomAttributeTypedArgument)
        If cata.Value.GetType() Is GetType(ReadOnlyCollection(Of CustomAttributeTypedArgument)) Then
            Console.WriteLine("         Array of '{0}':", cata.ArgumentType)

            For Each cataElement As CustomAttributeTypedArgument In cata.Value
                Console.WriteLine("             Type: '{0}'  Value: '{1}'", _
                    cataElement.ArgumentType, cataElement.Value)
            Next
        Else
            Console.WriteLine("         Type: '{0}'  Value: '{1}'", _
                cata.ArgumentType, cata.Value)
        End If       
    End Sub
End Class

' This code example produces output similar to the following:
'
'Attributes for assembly: 'source, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'
'   [System.Runtime.CompilerServices.CompilationRelaxationsAttribute((Int32)8)]
'      Constructor: 'Void .ctor(Int32)'
'      Constructor arguments:
'         Type: 'System.Int32'  Value: '8'
'      Named arguments:
'   [System.Runtime.CompilerServices.RuntimeCompatibilityAttribute(WrapNonExceptionThrows = True)]
'      Constructor: 'Void .ctor()'
'      Constructor arguments:
'      Named arguments:
'         MemberInfo: 'Boolean WrapNonExceptionThrows'
'         Type: 'System.Boolean'  Value: 'True'
'   [ExampleAttribute((ExampleKind)2, Note = "This is a note on the assembly.")]
'      Constructor: 'Void .ctor(ExampleKind)'
'      Constructor arguments:
'         Type: 'ExampleKind'  Value: '2'
'      Named arguments:
'         MemberInfo: 'System.String Note'
'         Type: 'System.String'  Value: 'This is a note on the assembly.'
'
'Attributes for type: 'Test'
'   [ExampleAttribute((ExampleKind)1, new String[3] { "String array argument, line 1", "String array argument, line 2", "String array argument, line 3" }, Note = "This is a note on the class.", Numbers = new Int32[3] { 53, 57, 59 })]
'      Constructor: 'Void .ctor(ExampleKind, System.String[])'
'      Constructor arguments:
'         Type: 'ExampleKind'  Value: '1'
'         Array of 'System.String[]':
'             Type: 'System.String'  Value: 'String array argument, line 1'
'             Type: 'System.String'  Value: 'String array argument, line 2'
'             Type: 'System.String'  Value: 'String array argument, line 3'
'      Named arguments:
'         MemberInfo: 'System.String Note'
'         Type: 'System.String'  Value: 'This is a note on the class.'
'         MemberInfo: 'Int32[] Numbers'
'         Array of 'System.Int32[]':
'             Type: 'System.Int32'  Value: '53'
'             Type: 'System.Int32'  Value: '57'
'             Type: 'System.Int32'  Value: '59'
'
'Attributes for member: 'Void TestMethod(System.Object)'
'   [ExampleAttribute(Note = "This is a note on a method.")]
'      Constructor: 'Void .ctor()'
'      Constructor arguments:
'      Named arguments:
'         MemberInfo: 'System.String Note'
'         Type: 'System.String'  Value: 'This is a note on a method.'
'
'Attributes for parameter: 'System.Object arg'
'   [ExampleAttribute()]
'      Constructor: 'Void .ctor()'
'      Constructor arguments:
'      Named arguments:

Hinweise

Code, der im reinen Spiegelungskontext untersucht wird, kann nicht immer ausgeführt werden, sodass es nicht immer möglich ist, benutzerdefinierte Attribute zu untersuchen, indem Instanzen von ihnen erstellt und dann ihre Eigenschaften mithilfe von Methoden wie Attribute.GetCustomAttributes, MemberInfo.GetCustomAttributesusw. untersucht werden. Wenn der Code für den Attributtyp selbst in den Nur-Spiegelungskontext geladen wird, kann er nicht ausgeführt werden.

Die CustomAttributeNamedArgument-Struktur wird von der CustomAttributeData-Klasse verwendet, um Zugriff auf den Typ und den Wert eines für eine benutzerdefinierte Attributinstanz angegebenen Positionsarguments bereitzustellen, ohne den Attributkonstruktor auszuführen. Außerdem bietet sie Zugriff auf den Typ und den Wert eines benannten Arguments, ohne den Code der entsprechenden Eigenschaft des benutzerdefinierten Attributtyps auszuführen.

Die Typen und Werte aller Positions- und benannten Argumente einer Attributinstanz werden von CustomAttributeTypedArgument Strukturen bereitgestellt. Die positionalen Attribute, die von der CustomAttributeData.ConstructorArguments-Eigenschaft zurückgegeben werden, werden direkt durch CustomAttributeTypedArgument Strukturen dargestellt, aber die benannten Argumente, die von der CustomAttributeData.NamedArguments-Eigenschaft zurückgegeben werden, werden durch CustomAttributeNamedArgument Strukturen dargestellt; Um die CustomAttributeTypedArgument Struktur für ein benanntes Argument abzurufen, verwenden Sie die CustomAttributeNamedArgument.TypedValue-Eigenschaft.

Wenn ein Argument ein Array von Werten ist, gibt die Value-Eigenschaft des CustomAttributeTypedArgument, das das Argument darstellt, eine generische ReadOnlyCollection<T> von CustomAttributeTypedArgument-Objekten zurück. Jedes CustomAttributeTypedArgument -Objekt in der Auflistung stellt das entsprechende Element des Arrays dar.

Verwenden Sie die staticGetCustomAttributes Factorymethode, um Instanzen der CustomAttributeData Klasse zu erstellen.

Konstruktoren

Eigenschaften

Methoden

Operatoren

Gilt für:

Weitere Informationen

• CustomAttributeData
• CustomAttributeNamedArgument
• ReflectionOnlyLoad