PropertyInfo.CanWriteとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

PropertyInfo.CanWrite プロパティ

プロパティに書き込むことができるかどうかを示す値を取得します。

名前空間: System.Reflection
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public MustOverride ReadOnly
 Property CanWrite As Boolean

Visual Basic (使用法)

Dim instance As PropertyInfo
Dim value As Boolean

value = instance.CanWrite

public abstract bool CanWrite { get;
 }

C++

public:
virtual property bool CanWrite {
    bool get () abstract;
}

/** @property */
public abstract boolean get_CanWrite ()

JScript

public abstract function get
 CanWrite () : boolean

プロパティ値
このプロパティに書き込むことができる場合は true。それ以外の場合は false。

解説

プロパティに set アクセサがない場合は、書き込むことができません。

CanWrite プロパティを取得するには、最初に Type クラスを取得します。そして、その Type から PropertyInfo を取得します。最後に、PropertyInfo から CanWrite を取得します。

使用例

2 つのプロパティを定義する例を次に示します。最初のプロパティは書き込み可能で、CanWrite プロパティは true です。2 番目のプロパティは書き込み不可で (set アクセサなし)、CanWrite プロパティは false です。

Visual Basic

Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic

' 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

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;
    }
}

C++

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;
}

import System.*;
import System.Reflection.*;

// Define one writable property and one not writable.
public class MyPropertyA
{
    private String caption = "A Default caption";

    /** @property 
     */
    public String get_Caption()
    {
        return caption ;
    } //get_Caption

    /** @property 
     */
    public void set_Caption (String value)
    {
        if (caption != value) {
            caption = value;
        }
    } //set_Caption
} //MyPropertyA

public class MyPropertyB
{
    private String caption = "B Default caption";

    /** @property 
     */
    public String get_Caption()
    {
        return caption ;
    } //get_Caption
} //MyPropertyB

class MyPropertyInfo
{   
    public static void main(String[]
 args)
    {
        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.get_Caption()));
        Console.Write(("\nMyPropertyB.Caption = " 
            + myPropertyB.get_Caption()));

        // Write to the property.
        myPropertyA.set_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.get_Caption()));
        Console.Write(("\nMyPropertyB.Caption = " 
            + myPropertyB.get_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 - " 
            + System.Convert.ToString(myPropertyInfoA.get_CanWrite())));
        Console.Write(("\nCanWrite B - " 
            + System.Convert.ToString(myPropertyInfoB.get_CanWrite())));
     } //main
} //MyPropertyInfo

JScript

import System;
import System.Reflection;

//Make two properties, one writable and one not writable 
public class Mypropertya
{
   private var caption : String = "A Default
 caption";
   public function get Caption()
 : String {
       return caption;
   }
   public function set Caption(value:String)
 {
       if(caption!=value) {caption = value;}
   }
}
public class Mypropertyb
{
   private var caption : String = "B Default
 caption";
   public function get Caption()
 : String {
       return caption;
   }
}
 
class Mypropertyinfo
{
   public static function
 Main() : void
   {
      Console.WriteLine("\nReflection.PropertyInfo");
 
      //Build two properties
      var mypropertya : Mypropertya = new Mypropertya();
      var 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- I have been changed";
      //Note: Mypropertyb.Caption cannot be written as
      // 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
      var MyTypea : Type = Type.GetType("Mypropertya");
      var Mypropertyinfoa : PropertyInfo = MyTypea.GetProperty("Caption");
      var MyTypeb : Type = Type.GetType("Mypropertyb");
      var Mypropertyinfob : PropertyInfo = MyTypeb.GetProperty("Caption");
 
      //Get and display the CanWrite property
     
      Console.Write("\nCanWrite a - " + Mypropertyinfoa.CanWrite);
     
      Console.Write("\nCanWrite b - " + Mypropertyinfob.CanWrite);
   }
}
Mypropertyinfo.Main();
/*
This code produces the following output:

Reflection.PropertyInfo

mypropertya.Caption = A Default caption
mypropertyb.Caption = B Default caption
mypropertya.Caption = A- I have been changed
mypropertyb.Caption = B Default caption
CanWrite a - true
CanWrite b - false
*/

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
PropertyInfo クラス
PropertyInfo メンバ
System.Reflection 名前空間

_PropertyInfo.CanWrite プロパティ

メモ : このプロパティは、.NET Framework version 2.0 で新しく追加されたものです。

COM オブジェクトに、CanWrite プロパティへのバージョンに依存しないアクセスが用意されています。

このプロパティは、CLS に準拠していません。

名前空間: System.Runtime.InteropServices
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

ReadOnly Property CanWrite As
 Boolean

Visual Basic (使用法)

Dim instance As _PropertyInfo
Dim value As Boolean

value = instance.CanWrite

bool CanWrite { get; }

C++

property bool CanWrite {
    bool get ();
}

/** @property */
boolean get_CanWrite ()

JScript

function get CanWrite () : boolean

プロパティ値
このプロパティに書き込むことができる場合は true。それ以外の場合は false。

解説

このプロパティは、アンマネージコードからマネージクラスにアクセスするためのプロパティであるため、マネージコードからは呼び出さないでください。

CanWrite プロパティは、プロパティに書き込むことができるかどうかを示す値を取得します。

プラットフォーム

バージョン情報

.NET Framework
サポート対象 : 2.0

参照

関連項目
_PropertyInfo インターフェイス
_PropertyInfo メンバ
System.Runtime.InteropServices 名前空間

>> 「PropertyInfo.CanWrite」を含む用語の索引
PropertyInfo.CanWriteのページへのリンク


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PropertyInfo.CanWriteとは？ わかりやすく解説

PropertyInfo.CanWrite プロパティ

_PropertyInfo.CanWrite プロパティ

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PropertyInfo.CanWriteとは？わかりやすく解説