FieldInfo.IsInitOnly プロパティ

public:
 property bool IsInitOnly { bool get(); };

public bool IsInitOnly { get; }

member this.IsInitOnly : bool

Public ReadOnly Property IsInitOnly As Boolean

プロパティ値

フィールドに 属性が設定されている場合は 2a0/& 。それ以外の場合は。

実装

例

次の例では、2 つのフィールドが作成されます。 2 番目のフィールドは読み取り専用で、アクセサーは設定されておらず、 IsInitOnly は trueに設定されます。

using System;
using System.Reflection;

//Make two fields, one public and one read-only.
public class Myfielda
{
    public string field = "A - public modifiable field";
}
public class Myfieldb
{
    public readonly string field = "B - readonly field";
}

public class Myfieldinfo
{
    public static int Main()
    {
        Console.WriteLine("\nReflection.FieldInfo");
        Myfielda Myfielda = new Myfielda();
        Myfieldb Myfieldb = new Myfieldb();

        //Get the Type and FieldInfo.
        Type MyTypea = typeof(Myfielda);
        FieldInfo Myfieldinfoa = MyTypea.GetField("field",
            BindingFlags.Public | BindingFlags.Instance);
        Type MyTypeb = typeof(Myfieldb);
        FieldInfo Myfieldinfob = MyTypeb.GetField("field",
            BindingFlags.Public | BindingFlags.Instance);

        //Modify the fields.
        //Note that Myfieldb is not modified, as it is
        //read-only (IsInitOnly is True).
        Myfielda.field = "A - modified";
        //Myfieldb.field = "B - modified";

        //For the first field, get and display the name, field, and IsInitOnly state.
        Console.Write("\n{0} - {1}, IsInitOnly = {2} ",
            MyTypea.FullName,
            Myfieldinfoa.GetValue(Myfielda),
            Myfieldinfoa.IsInitOnly);

        //For the second field get and display the name, field, and IsInitOnly state.
        Console.Write("\n{0} - {1}, IsInitOnly = {2} ",
            MyTypeb.FullName,
            Myfieldinfob.GetValue(Myfieldb),
            Myfieldinfob.IsInitOnly);

        return 0;
    }
}

Imports System.Reflection

'Make two fields, one public and one read-only.
Public Class Myfielda
    Public field As String = "A - public modifiable field"
End Class

Public Class Myfieldb
    Public ReadOnly field As String = "B - readonly field"
End Class

Public Class Myfieldinfo
    Public Shared Function Main() As Integer
        Console.WriteLine("Reflection.FieldInfo")
        Console.WriteLine()
        Dim Myfielda As New Myfielda()
        Dim Myfieldb As New Myfieldb()

        'Get the Type and FieldInfo.
        Dim MyTypea As Type = GetType(Myfielda)
        Dim Myfieldinfoa As FieldInfo = MyTypea.GetField("field", _
            BindingFlags.Public Or BindingFlags.Instance)
        Dim MyTypeb As Type = GetType(Myfieldb)
        Dim Myfieldinfob As FieldInfo = MyTypeb.GetField("field", _
            BindingFlags.Public Or BindingFlags.Instance)

        'Modify the fields.
        'Note that Myfieldb is not modified, as it is
        'read-only (IsInitOnly is True).
        Myfielda.field = "A - modified"
        'For the first field, get and display the name, field, and IsInitOnly state.
        Console.WriteLine("{0} - {1}, IsInitOnly = {2} ", MyTypea.FullName, _
            Myfieldinfoa.GetValue(Myfielda), Myfieldinfoa.IsInitOnly)
        'For the second field get and display the name, field, and IsInitOnly state.
        Console.WriteLine("{0} - {1}, IsInitOnly = {2} ", MyTypeb.FullName, _
            Myfieldinfob.GetValue(Myfieldb), Myfieldinfob.IsInitOnly)

        Return 0
    End Function 'Main
End Class

このコードでは、次の出力が生成されます。

Reflection.FieldInfo

Myfielda - A- modified, IsInitOnly = False

Myfieldb - B readonly field, IsInitOnly = True

注釈

戻り値が trueの場合、フィールドは初期化することしかでき、それ以降は読み取り専用です。

IsInitOnly プロパティを取得するには、まずクラス Typeを取得します。 Typeから、FieldInfoを取得します。 FieldInfoから、IsInitOnly プロパティを取得します。 パブリックフィールドにアクセスするには、BindingFlags.NonPublicをBindingFlags.StaticメソッドのBindingFlags.InstanceとGetFieldのいずれかまたは両方と組み合わせます。

IsInitOnly属性が設定されると、FieldAttributes.InitOnly プロパティが設定されます。

こちらもご覧ください

• FieldAttributes
• GetField(String, BindingFlags)
• Type