PropertyInfo.CanRead Właściwość

Definicja

Przestrzeń nazw:

System.Reflection

Zestaw:

System.Runtime.dll

Źródło:

PropertyInfo.cs

Pobiera wartość wskazującą, czy właściwość można odczytać.

public:
 abstract property bool CanRead { bool get(); };

public abstract bool CanRead { get; }

member this.CanRead : bool

Public MustOverride ReadOnly Property CanRead As Boolean

Wartość właściwości

Boolean

true jeśli ta właściwość może być odczytywana; w przeciwnym razie , false.

Przykłady

W poniższym przykładzie zdefiniowano dwie właściwości. Pierwsza właściwość jest czytelna, a CanRead właściwość to true. Druga właściwość nie jest czytelna (nie ma metody uzyskiwania dostępu), a CanRead właściwość to false.

using namespace System;
using namespace System::Reflection;

// Define one readable property and one not readable.
public ref class Mypropertya
{
private:
   String^ caption;

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


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

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

   }

};

public ref class Mypropertyb
{
private:
   String^ caption;

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


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

   }

};

int main()
{
   Console::WriteLine( "\nReflection.PropertyInfo" );
   
   // Define two properties.
   Mypropertya^ mypropertya = gcnew Mypropertya;
   Mypropertyb^ mypropertyb = gcnew Mypropertyb;
   Console::Write( "\nMypropertya->Caption = {0}", mypropertya->Caption );
   
   // Mypropertyb.Caption cannot be read, because
   // there is no get accessor.
   // Get the type and PropertyInfo.
   Type^ MyTypea = Type::GetType( "Mypropertya" );
   PropertyInfo^ Mypropertyinfoa = MyTypea->GetProperty( "Caption" );
   Type^ MyTypeb = Type::GetType( "Mypropertyb" );
   PropertyInfo^ Mypropertyinfob = MyTypeb->GetProperty( "Caption" );
   
   // Get and display the CanRead property.
   Console::Write( "\nCanRead a - {0}", Mypropertyinfoa->CanRead );
   Console::Write( "\nCanRead b - {0}", Mypropertyinfob->CanRead );
   return 0;
}

using System;
using System.Reflection;

// Define one readable property and one not readable.
public class Mypropertya
{
    private string caption = "A Default caption";
    public string Caption
    {
        get{return caption;}
        set {if(caption!=value) {caption = value;}
        }
    }
}
public class Mypropertyb
{
    private string caption = "B Default caption";
    public string Caption
    {
        set{if(caption!=value) {caption = value;}
        }
    }
}

class Mypropertyinfo
{
    public static int Main()
    {
        Console.WriteLine("\nReflection.PropertyInfo");

        // Define two properties.
        Mypropertya Mypropertya = new Mypropertya();
        Mypropertyb Mypropertyb = new Mypropertyb();

        Console.Write("\nMypropertya.Caption = " + Mypropertya.Caption);
        // Mypropertyb.Caption cannot be read, because
        // there is no get accessor.

        // Get the type and PropertyInfo.
        Type MyTypea = Type.GetType("Mypropertya");
        PropertyInfo Mypropertyinfoa = MyTypea.GetProperty("Caption");
        Type MyTypeb = Type.GetType("Mypropertyb");
        PropertyInfo Mypropertyinfob = MyTypeb.GetProperty("Caption");

        // Get and display the CanRead property.
        Console.Write("\nCanRead a - " + Mypropertyinfoa.CanRead);
        Console.Write("\nCanRead b - " + Mypropertyinfob.CanRead);

        return 0;
    }
}

Imports System.Reflection

' Define one readable property and one not readable.
Public Class Mypropertya
    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 Mypropertyb
    Private myCaption As String = "B Default caption"

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

Class Mypropertyinfo

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

        ' Define two properties.
        Dim Mypropertya As New Mypropertya()
        Dim Mypropertyb As New Mypropertyb()

        Console.Write(ControlChars.Cr & "Mypropertya.Caption = " & _
           Mypropertya.Caption)
        ' Mypropertyb.Caption cannot be read because
        ' there is no get accessor.
        ' Get the type and PropertyInfo.
        Dim MyTypea As Type = Type.GetType("Mypropertya")
        Dim Mypropertyinfoa As PropertyInfo = MyTypea.GetProperty("Caption")
        Dim MyTypeb As Type = Type.GetType("Mypropertyb")
        Dim Mypropertyinfob As PropertyInfo = MyTypeb.GetProperty("Caption")

        ' Get and display the CanRead property.
        Console.Write(ControlChars.CrLf & "CanRead a - " & _
           Mypropertyinfoa.CanRead)

        Console.Write(ControlChars.CrLf & "CanRead b - " & _
           Mypropertyinfob.CanRead)

        Return 0
    End Function
End Class

Uwagi

Jeśli właściwość nie ma get metody dostępu, nie można jej odczytać.

Aby uzyskać właściwość, najpierw pobierz klasę CanReadType. W pliku Typepobierz element PropertyInfo. Z elementu PropertyInfopobierz CanRead wartość .