PropertyInfo.CanWrite Свойство

Определение

Получает значение, указывающее, можно ли производить запись в данное свойство.Gets a value indicating whether the property can be written to.

public:
 abstract property bool CanWrite { bool get(); };
public abstract bool CanWrite { get; }
member this.CanWrite : bool
Public MustOverride ReadOnly Property CanWrite As Boolean

Значение свойства

Boolean

Значение true, если свойство доступно для записи; в обратном случае — значение false.true if this property can be written to; otherwise, false.

Реализации

Примеры

В следующем примере определяются два свойства.The following example defines two properties. Первое свойство доступно для записи, а CanWrite свойство — true .The first property is writable and the CanWrite property is true. Второе свойство недоступно для записи (отсутствует set метод доступа), а CanWrite свойство имеет значение false .The second property is not writable (there is no set accessor), and the CanWrite property is false.

using namespace System;
using namespace System::Reflection;

// Define one writable property and one not writable.
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 
   {
      String^ get()
      {
         return caption;
      }

   }

};

int main()
{
   Console::WriteLine( "\nReflection.PropertyInfo" );
   
   // Define two properties.
   Mypropertya^ mypropertya = gcnew Mypropertya;
   Mypropertyb^ mypropertyb = gcnew Mypropertyb;
   
   // Read and display the property.
   Console::Write( "\nMypropertya->Caption = {0}", mypropertya->Caption );
   Console::Write( "\nMypropertyb->Caption = {0}", mypropertyb->Caption );
   
   // Write to the property.
   mypropertya->Caption = "A- No Change";
   
   // Mypropertyb.Caption cannot be written to because
   // there is no set accessor.
   // Read and display the property.
   Console::Write( "\nMypropertya->Caption = {0}", mypropertya->Caption );
   Console::Write( "\nMypropertyb->Caption = {0}", mypropertyb->Caption );
   
   // 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 CanWrite property.
   Console::Write( "\nCanWrite a - {0}", Mypropertyinfoa->CanWrite );
   Console::Write( "\nCanWrite b - {0}", Mypropertyinfob->CanWrite );
   return 0;
}

using System;
using System.Reflection;

 // Define one writable property and one not writable.
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
    {
        get{return caption;}
    }
}

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

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

        // Read and display the property.
        Console.Write("\nMypropertya.Caption = " + Mypropertya.Caption);
        Console.Write("\nMypropertyb.Caption = " + Mypropertyb.Caption);

        // Write to the property.
        Mypropertya.Caption = "A- No Change";
        // Mypropertyb.Caption cannot be written to because
        // there is no set accessor.

        // Read and display the property.
        Console.Write("\nMypropertya.Caption = " + Mypropertya.Caption);
        Console.Write ("\nMypropertyb.Caption = " + Mypropertyb.Caption);

        // 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 CanWrite property.

        Console.Write("\nCanWrite a - " + Mypropertyinfoa.CanWrite);

        Console.Write("\nCanWrite b - " + Mypropertyinfob.CanWrite);

        return 0;
    }
}
Imports System.Reflection

' Define one writable property and one not writable.
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 ReadOnly Property Caption() As String
        Get
            Return myCaption
        End Get
    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()

        ' Read and display the property.
        Console.Write(ControlChars.CrLf & "Mypropertya.Caption = " & _
           Mypropertya.Caption)
        Console.Write(ControlChars.CrLf & "Mypropertyb.Caption = " & _
           Mypropertyb.Caption)

        ' Write to the property.
        Mypropertya.Caption = "A- No Change"
        ' Mypropertyb.Caption cannot be written to because
        ' there is no set accessor.
        ' Read and display the property.
        Console.Write(ControlChars.CrLf & "Mypropertya.Caption = " & _
           Mypropertya.Caption)
        Console.Write(ControlChars.CrLf & "Mypropertyb.Caption = " & _
           Mypropertyb.Caption)

        ' 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 CanWrite property.
        Console.Write(ControlChars.CrLf & "CanWrite a - " & _
           Mypropertyinfoa.CanWrite)

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

        Return 0
    End Function
End Class

Комментарии

CanWrite Возвращает, true Если свойство имеет set метод доступа, даже если метод доступа имеет private значение internal (или Friend в Visual Basic) или protected .CanWrite returns true if the property has a set accessor, even if the accessor is private, internal (or Friend in Visual Basic), or protected. Если свойство не имеет set метода доступа, метод возвращает значение false .If the property does not have a set accessor, the method returns false.

Чтобы получить значение CanWrite свойства, сделайте следующее:To get the value of the CanWrite property:

  1. Возвращает Type объект типа, включающий свойство.Get the Type object of the type that includes the property.

  2. Вызовите метод, Type.GetProperty чтобы получить PropertyInfo объект, представляющий свойство.Call the Type.GetProperty to get the PropertyInfo object that represents the property.

  3. Получение значения CanWrite Свойства.Retrieve the value of the CanWrite property.

Применяется к