PropertyAttributes Enumerazione

  • Riferimento

Definizione

Spazio dei nomi:
System.Reflection
Assembly:
System.Reflection.Primitives.dll
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll

Definisce gli attributi che è possibile associare a una proprietà. Questi valori di attributo sono definiti nel file corhdr.h.

Questa enumerazione supporta una combinazione bit per bit dei rispettivi valori dei membri.

public enum class PropertyAttributes
[System.Flags]
public enum PropertyAttributes
[System.Flags]
[System.Serializable]
public enum PropertyAttributes
[System.Flags]
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public enum PropertyAttributes
[<System.Flags>]
type PropertyAttributes = 
[<System.Flags>]
[<System.Serializable>]
type PropertyAttributes = 
[<System.Flags>]
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type PropertyAttributes = 
Public Enum PropertyAttributes
Ereditarietà
Object
ValueType
Enum
PropertyAttributes
Attributi
FlagsAttribute SerializableAttribute ComVisibleAttribute

Campi

HasDefault 4096

Specifica che la proprietà ha un valore predefinito.
None 0

Specifica che nessun attributo è associato a una proprietà.
Reserved2 8192

Riservato.
Reserved3 16384

Riservato.
Reserved4 32768

Riservato.
ReservedMask 62464

Specifica un flag riservato unicamente per l'utilizzo in fase di esecuzione.
RTSpecialName 1024

Specifica che le API interne dei metadati controllano la codifica dei nomi.
SpecialName 512

Specifica che la proprietà è speciale e tale caratteristica è indicata dal nome.

Esempio

Nell'esempio seguente vengono compilate tre proprietà e viene visualizzato il PropertyAttributes valore enumerato. Si noti che la proprietà di sola lettura non ha alcun setter e pertanto non può essere modificata da.Caption = statement

using namespace System;
using namespace System::Reflection;

// Define three properties: one read-write, one default,
// and one read only. 
// Define a read-write property.
public ref class Aproperty
{
private:
   String^ caption;

public:
   Aproperty()
      : caption( "A Default caption" )
   {}


   property String^ Caption 
   {
      String^ get()
      {
         return caption;
      }

      void set( String^ value )
      {
         if ( caption != value )
         {
            caption = value;
         }
      }

   }

};


// Define a default property.
public ref class Bproperty
{
private:
   String^ caption;

public:
   Bproperty()
      : caption( "B Default caption" )
   {}

public:
   property String^ Item
   {
      String^ get()
      {
         return "1";
      }

   }

   property String^ Caption 
   {
      String^ get()
      {
         return caption;
      }

      void set( String^ value )
      {
         if ( caption != value )
         {
            caption = value;
         }
      }

   }

};


// Define a read-only property.
public ref class Cproperty
{
private:
   String^ caption;

public:
   Cproperty()
      : caption( "C Default caption" )
   {}


   property String^ Caption 
   {
      String^ get()
      {
         return caption;
      }

   }

};

int main()
{
   Console::WriteLine( "\nReflection.PropertyAttributes" );
   
   // Determine whether a property exists, and change its value.
   Aproperty^ Mypropertya = gcnew Aproperty;
   Bproperty^ Mypropertyb = gcnew Bproperty;
   Cproperty^ Mypropertyc = gcnew Cproperty;
   Console::Write( "\n1. Mypropertya->Caption = {0}", Mypropertya->Caption );
   Console::Write( "\n1. Mypropertyb->Caption = {0}", Mypropertyb->Caption );
   Console::Write( "\n1. Mypropertyc->Caption = {0}", Mypropertyc->Caption );
   
   // Only Mypropertya can be changed, as Mypropertyb is read-only.
   Mypropertya->Caption = "A- This is changed.";
   Mypropertyb->Caption = "B- This is changed.";
   
   // Note that Mypropertyc is not changed because it is read only
   Console::Write( "\n\n2. Mypropertya->Caption = {0}", Mypropertya->Caption );
   Console::Write( "\n2. Mypropertyb->Caption = {0}", Mypropertyb->Caption );
   Console::Write( "\n2. Mypropertyc->Caption = {0}", Mypropertyc->Caption );
   
   // Get the PropertyAttributes enumeration of the property.
   // Get the type.
   Type^ MyTypea = Type::GetType( "Aproperty" );
   Type^ MyTypeb = Type::GetType( "Bproperty" );
   Type^ MyTypec = Type::GetType( "Cproperty" );

   // Get the property attributes.
   PropertyInfo^ Mypropertyinfoa = MyTypea->GetProperty( "Caption" );
   PropertyAttributes Myattributesa = Mypropertyinfoa->Attributes;
   PropertyInfo^ Mypropertyinfob = MyTypeb->GetProperty( "Item" );
   PropertyAttributes Myattributesb = Mypropertyinfob->Attributes;
   PropertyInfo^ Mypropertyinfoc = MyTypec->GetProperty( "Caption" );
   PropertyAttributes Myattributesc = Mypropertyinfoc->Attributes;

   // Display the property attributes value.
   Console::Write( "\n\na- {0}", Myattributesa );
   Console::Write( "\nb- {0}", Myattributesb );
   Console::Write( "\nc- {0}", Myattributesc );
   return 0;
}

// This example displays the following output to the console
//
// Reflection.PropertyAttributes
//
// 1. Mypropertya.Caption = A Default caption
// 1. Mypropertyb.Caption = B Default caption
// 1. Mypropertyc.Caption = C Default caption
//
// 2. Mypropertya.Caption = A- This is changed.
// 2. Mypropertyb.Caption = B- This is changed.
// 2. Mypropertyc.Caption = C Default caption
//
// a- None
// b- None
// c- None

using System;
using System.Reflection;

 // Define three properties: one read-write, one default,
 // and one read only.
public class Aproperty
    // Define a read-write property.
{
    private string caption = "A Default caption";
    public string Caption
    {
        get{return caption;}
        set
        {
            if (caption != value){caption = value;}
        }
    }
}
public class Bproperty
    // Define a default property.
{
    private string caption  = "B Default caption";
    public string this [int index]
    {
        get {return "1";}
    }
    public string Caption
    {

        get{return caption;}
        set
        {
            if (caption != value){caption = value;}
        }
    }
}
public class Cproperty
    // Define a read-only property.
{
    private string caption = "C Default caption";
    public string Caption
    {
        get{return caption;}
        // No setting is allowed, because this is a read-only property.
    }
}

class propertyattributesenum
{
    public static int Main(string[] args)
    {
        Console.WriteLine("\nReflection.PropertyAttributes");

        // Determine whether a property exists, and change its value.
        Aproperty Mypropertya = new Aproperty();
        Bproperty Mypropertyb = new Bproperty();
        Cproperty Mypropertyc = new Cproperty();

        Console.Write("\n1. Mypropertya.Caption = " + Mypropertya.Caption );

        Console.Write("\n1. Mypropertyb.Caption = " + Mypropertyb.Caption );

        Console.Write("\n1. Mypropertyc.Caption = " + Mypropertyc.Caption );

        // Only Mypropertya can be changed, as Mypropertyb is read-only.
        Mypropertya.Caption = "A- This is changed.";
        Mypropertyb.Caption = "B- This is changed.";
        // Note that Mypropertyc is not changed because it is read only

        Console.Write("\n\n2. Mypropertya.Caption = " + Mypropertya.Caption );

        Console.Write("\n2. Mypropertyb.Caption = " + Mypropertyb.Caption );

        Console.Write("\n2. Mypropertyc.Caption = " + Mypropertyc.Caption );

        // Get the PropertyAttributes enumeration of the property.
        // Get the type.
        Type MyTypea = Type.GetType("Aproperty");
        Type MyTypeb = Type.GetType("Bproperty");
        Type MyTypec = Type.GetType("Cproperty");

        // Get the property attributes.
        PropertyInfo Mypropertyinfoa = MyTypea.GetProperty("Caption");
        PropertyAttributes Myattributesa = Mypropertyinfoa.Attributes;
        PropertyInfo Mypropertyinfob = MyTypeb.GetProperty("Item");
        PropertyAttributes Myattributesb = Mypropertyinfob.Attributes;
        PropertyInfo Mypropertyinfoc = MyTypec.GetProperty("Caption");
        PropertyAttributes Myattributesc = Mypropertyinfoc.Attributes;

        // Display the property attributes value.

        Console.Write("\n\na- " + Myattributesa.ToString());

        Console.Write("\nb- " + Myattributesb.ToString());

        Console.Write("\nc- " + Myattributesc.ToString());
        return 0;
    }
}

// This example displays the following output to the console
//
// Reflection.PropertyAttributes
//
// 1. Mypropertya.Caption = A Default caption
// 1. Mypropertyb.Caption = B Default caption
// 1. Mypropertyc.Caption = C Default caption
//
// 2. Mypropertya.Caption = A- This is changed.
// 2. Mypropertyb.Caption = B- This is changed.
// 2. Mypropertyc.Caption = C Default caption
//
// a- None
// b- None
// c- None

Imports System.Reflection

' Make three properties, one read-write, one default,
' and one read-only. 
Public Class Aproperty
    ' Define a read-write property.
    Private myCaption As String = "A Default caption"

    Public Property Caption() As String
        Get
            Return myCaption
        End Get
        Set(ByVal Value As String)
            If myCaption <> value Then
                myCaption = value
            End If
        End Set
    End Property
End Class

Public Class Bproperty
    ' Define a default property.
    Private myCaption As String = "B Default caption"

    Default Public ReadOnly Property Item(ByVal index As Integer) As String
        Get
            Return "1"
        End Get
    End Property

    Public Property Caption() As String

        Get
            Return myCaption
        End Get
        Set(ByVal Value As String)
            If myCaption <> value Then
                myCaption = value
            End If
        End Set
    End Property
End Class

Public Class Cproperty
    ' Define a read-only property.
    Private myCaption As String = "C Default caption"

    Public ReadOnly Property Caption() As String
        Get
            Return myCaption
        End Get
        'No setting is allowed because this property is read-only.
    End Property
End Class


Class propertyattributesenum

    Public Shared Function Main() As Integer
        Console.WriteLine(ControlChars.CrLf & "Reflection.PropertyAttributes")

        ' Determine whether a property exists, and change its value.
        Dim Mypropertya As New Aproperty()
        Dim Mypropertyb As New Bproperty()
        Dim Mypropertyc As New Cproperty()

        Console.Write(ControlChars.CrLf & "1. Mypropertya.Caption = " & _
           Mypropertya.Caption)

        Console.Write(ControlChars.CrLf & "1. Mypropertyb.Caption = " & _
           Mypropertyb.Caption)

        Console.Write(ControlChars.CrLf & "1. Mypropertyc.Caption = " & _
           Mypropertyc.Caption)

        ' Only Mypropertya can be changed because Mypropertyb is read-only.
        Mypropertya.Caption = "A- This is changed."
        Mypropertyb.Caption = "B- This is changed."
        ' Note that Mypropertyc is not changed, because it is read-only.
        Console.Write(ControlChars.CrLf & ControlChars.CrLf & _
           "2. Mypropertya.Caption = " & Mypropertya.Caption)

        Console.Write(ControlChars.CrLf & "2. Mypropertyb.Caption = " & _
           Mypropertyb.Caption)

        Console.Write(ControlChars.CrLf + "2. Mypropertyc.Caption = " & _
           Mypropertyc.Caption)

        ' Get the PropertyAttributes Enumeration of the property.
        ' Get the type.
        Dim MyTypea As Type = Type.GetType("Aproperty")
        Dim MyTypeb As Type = Type.GetType("Bproperty")
        Dim MyTypec As Type = Type.GetType("Cproperty")

        ' Get the property attributes.
        Dim Mypropertyinfoa As PropertyInfo = MyTypea.GetProperty("Caption")
        Dim Myattributesa As PropertyAttributes = Mypropertyinfoa.Attributes
        Dim Mypropertyinfob As PropertyInfo = MyTypeb.GetProperty("Item")
        Dim Myattributesb As PropertyAttributes = Mypropertyinfob.Attributes
        Dim Mypropertyinfoc As PropertyInfo = MyTypec.GetProperty("Caption")
        Dim Myattributesc As PropertyAttributes = Mypropertyinfoc.Attributes

        ' Display the property attributes value.
        Console.Write(ControlChars.CrLf & ControlChars.CrLf & "a- " & _
           Myattributesa.ToString())

        Console.Write(ControlChars.CrLf & "b- " & Myattributesb.ToString())

        Console.Write(ControlChars.CrLf & "c- " & Myattributesc.ToString())
        Return 0
    End Function'    End Function
End Class

' This example displays the following output to the console
'
' Reflection.PropertyAttributes
'
' 1. Mypropertya.Caption = A Default caption
' 1. Mypropertyb.Caption = B Default caption
' 1. Mypropertyc.Caption = C Default caption
'
' 2. Mypropertya.Caption = A- This is changed.
' 2. Mypropertyb.Caption = B- This is changed.
' 2. Mypropertyc.Caption = C Default caption
'
' a- None
' b- None
' c- None

Commenti

Per ottenere PropertyAttributes, ottenere prima di tutto la classe Type. Da ottenere l'oggetto TypePropertyInfo. Da ottenere l'oggetto PropertyInfoAttributes.

Il valore enumerato è un numero che rappresenta l'OR bit per bit degli attributi implementati nel metodo .

Si applica a