CA2240 : Implémentez ISerializable comme il se doit
TypeName |
ImplementISerializableCorrectly |
CheckId |
CA2240 |
Catégorie |
Microsoft.Usage |
Modification avec rupture |
Modification sans rupture |
Cause
Un type visible de l'extérieur peut être assigné à l'interface ISerializable et une des conditions suivantes est vraie :
Le type hérite de la méthode ISerializable.GetObjectData, mais ne la substitue pas, et il déclare des champs d'instance qui ne sont pas marqués avec l'attribut NonSerializedAttribute.
Le type n'est pas sealed (scellé) et il implémente une méthode GetObjectData qui n'est ni visible de l'extérieur, ni substituable.
Description de la règle
Les champs d'instance qui sont déclarés dans un type qui hérite de l'interface ISerializable ne sont pas automatiquement intégrés au processus de sérialisation.Pour intégrer les champs, le type doit implémenter la méthode GetObjectData et le constructeur de sérialisation.Si les champs ne doivent pas être sérialisés, appliquez l'attribut NonSerializedAttribute aux champs pour indiquer explicitement cette décision.
Dans les types non sealed, les implémentations de la méthode GetObjectData doivent être visibles extérieurement.Par conséquent, la méthode peut être appelée par des types dérivés et est substituable.
Comment corriger les violations
Pour corriger une violation de cette règle, rendez la méthode GetObjectData visible et substituable, et assurez-vous que tous les champs d'instance sont intégrés au processus de sérialisation ou sont marqués explicitement avec l'attribut NonSerializedAttribute.
Quand supprimer les avertissements
Ne supprimez aucun avertissement de cette règle.
Exemple
L'exemple suivant présente deux types sérialisables qui ne respectent pas la règle.
Imports System
Imports System.Security.Permissions
Imports System.Runtime.Serialization
Namespace Samples1
' Violates this rule
<Serializable()> _
Public Class Book
Implements ISerializable
Private ReadOnly _Title As String
Public Sub New(ByVal title As String)
If (title Is Nothing) Then Throw New ArgumentNullException("title")
_Title = title
End Sub
Protected Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
If (info Is Nothing) Then Throw New ArgumentNullException("info")
_Title = info.GetString("Title")
End Sub
Public ReadOnly Property Title() As String
Get
Return _Title
End Get
End Property
<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.SerializationFormatter)> _
Public Sub GetObjectData(ByVal info As SerializationInfo, ByVal context As StreamingContext) _
Implements ISerializable.GetObjectData
If (info Is Nothing) Then Throw New ArgumentNullException("info")
info.AddValue("Title", _Title)
End Sub
End Class
' Violates this rule
<Serializable()> _
Public Class LibraryBook
Inherits Book
Private ReadOnly _CheckedOut As Date
Public Sub New(ByVal text As String, ByVal checkedOut As Date)
MyBase.New(text)
_CheckedOut = checkedOut
End Sub
Public ReadOnly Property CheckedOut() As Date
Get
Return _CheckedOut
End Get
End Property
End Class
End Namespace
using System;
using System.Security.Permissions;
using System.Runtime.Serialization;
namespace Samples1
{
// Violates this rule
[Serializable]
public class Book : ISerializable
{
private readonly string _Text;
public Book(string text)
{
if (text == null)
throw new ArgumentNullException("text");
_Text = text;
}
protected Book(SerializationInfo info, StreamingContext context)
{
if (info == null)
throw new ArgumentNullException("info");
_Text = info.GetString("Text");
}
public string Text
{
get { return _Text; }
}
[SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
if (info == null)
throw new ArgumentNullException("info");
info.AddValue("Text", _Text);
}
}
// Violates this rule
[Serializable]
public class LibraryBook : Book
{
private readonly DateTime _CheckedOut;
public LibraryBook(string text, DateTime checkedOut)
: base(text)
{
_CheckedOut = checkedOut;
}
public DateTime CheckedOut
{
get { return _CheckedOut; }
}
}
}
using namespace System;
using namespace System::Security::Permissions;
using namespace System::Runtime::Serialization;
namespace Samples1
{
// Violates this rule
[Serializable]
public ref class Book : ISerializable
{
private:
initonly String^ _Title;
public:
Book(String^ title)
{
if (title == nullptr)
throw gcnew ArgumentNullException("title");
_Title = title;
}
property String^ Title
{
String^ get()
{
return _Title;
}
}
protected:
Book(SerializationInfo^ info, StreamingContext context)
{
if (info == nullptr)
throw gcnew ArgumentNullException("info");
_Title = info->GetString("Title");
}
private:
[SecurityPermission(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::SerializationFormatter)]
void virtual GetObjectData(SerializationInfo^ info, StreamingContext context) sealed = ISerializable::GetObjectData
{
if (info == nullptr)
throw gcnew ArgumentNullException("info");
info->AddValue("Title", _Title);
}
};
// Violates this rule
[Serializable]
public ref class LibraryBook : Book
{
initonly DateTime _CheckedOut;
public:
LibraryBook(String^ title, DateTime checkedOut) : Book(title)
{
_CheckedOut = checkedOut;
}
property DateTime CheckedOut
{
DateTime get()
{
return _CheckedOut;
}
}
};
}
L'exemple suivant résout les deux violations ci-dessus en fournissant une implémentation substituable de [ISerializable.GetObjectData] sur la classe Book et en fournissant une implémentation de [ISerializable.GetObjectData] sur la classe Library.
Imports System
Imports System.Security.Permissions
Imports System.Runtime.Serialization
Namespace Samples2
<Serializable()> _
Public Class Book
Implements ISerializable
Private ReadOnly _Title As String
Public Sub New(ByVal title As String)
If (title Is Nothing) Then Throw New ArgumentNullException("title")
_Title = title
End Sub
Protected Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
If (info Is Nothing) Then Throw New ArgumentNullException("info")
_Title = info.GetString("Title")
End Sub
Public ReadOnly Property Title() As String
Get
Return _Title
End Get
End Property
<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.SerializationFormatter)> _
Protected Overridable Sub GetObjectData(ByVal info As SerializationInfo, ByVal context As StreamingContext) _
Implements ISerializable.GetObjectData
If (info Is Nothing) Then Throw New ArgumentNullException("info")
info.AddValue("Title", _Title)
End Sub
End Class
<Serializable()> _
Public Class LibraryBook
Inherits Book
Private ReadOnly _CheckedOut As Date
Public Sub New(ByVal text As String, ByVal checkedOut As Date)
MyBase.New(text)
_CheckedOut = checkedOut
End Sub
Protected Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
MyBase.New(info, context)
_CheckedOut = info.GetDateTime("CheckedOut")
End Sub
Public ReadOnly Property CheckedOut() As Date
Get
Return _CheckedOut
End Get
End Property
<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.SerializationFormatter)> _
Protected Overrides Sub GetObjectData(ByVal info As System.Runtime.Serialization.SerializationInfo, _
ByVal context As System.Runtime.Serialization.StreamingContext)
MyBase.GetObjectData(info, context)
info.AddValue("CheckedOut", _CheckedOut)
End Sub
End Class
End Namespace
using System;
using System.Security.Permissions;
using System.Runtime.Serialization;
namespace Samples2
{
[Serializable]
public class Book : ISerializable
{
private readonly string _Title;
public Book(string title)
{
if (title == null)
throw new ArgumentNullException("title");
_Title = title;
}
protected Book(SerializationInfo info, StreamingContext context)
{
if (info == null)
throw new ArgumentNullException("info");
_Title = info.GetString("Title");
}
public string Title
{
get { return _Title; }
}
[SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
protected virtual void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("Title", _Title);
}
[SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.SerializationFormatter)]
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
if (info == null)
throw new ArgumentNullException("info");
GetObjectData(info, context);
}
}
[Serializable]
public class LibraryBook : Book
{
private readonly DateTime _CheckedOut;
public LibraryBook(string title, DateTime checkedOut)
: base(title)
{
_CheckedOut = checkedOut;
}
protected LibraryBook(SerializationInfo info, StreamingContext context)
: base(info, context)
{
_CheckedOut = info.GetDateTime("CheckedOut");
}
public DateTime CheckedOut
{
get { return _CheckedOut; }
}
[SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
protected override void GetObjectData(SerializationInfo info, StreamingContext context)
{
base.GetObjectData(info, context);
info.AddValue("CheckedOut", _CheckedOut);
}
}
}
using namespace System;
using namespace System::Security::Permissions;
using namespace System::Runtime::Serialization;
namespace Samples2
{
[Serializable]
public ref class Book : ISerializable
{
private:
initonly String^ _Title;
public:
Book(String^ title)
{
if (title == nullptr)
throw gcnew ArgumentNullException("title");
_Title = title;
}
property String^ Title
{
String^ get()
{
return _Title;
}
}
protected:
Book(SerializationInfo^ info, StreamingContext context)
{
if (info == nullptr)
throw gcnew ArgumentNullException("info");
_Title = info->GetString("Title");
}
[SecurityPermission(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::SerializationFormatter)]
void virtual GetObjectData(SerializationInfo^ info, StreamingContext context) = ISerializable::GetObjectData
{
if (info == nullptr)
throw gcnew ArgumentNullException("info");
info->AddValue("Title", _Title);
}
};
[Serializable]
public ref class LibraryBook : Book
{
initonly DateTime _CheckedOut;
public:
LibraryBook(String^ title, DateTime checkedOut)
: Book(title)
{
_CheckedOut = checkedOut;
}
property DateTime CheckedOut
{
DateTime get()
{
return _CheckedOut;
}
}
protected:
LibraryBook(SerializationInfo^ info, StreamingContext context) : Book(info, context)
{
_CheckedOut = info->GetDateTime("CheckedOut");
}
[SecurityPermission(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::SerializationFormatter)]
void virtual GetObjectData(SerializationInfo^ info, StreamingContext context) override
{
Book::GetObjectData(info, context);
info->AddValue("CheckedOut", _CheckedOut);
}
};
}
Règles connexes
CA2236 : Appelez les méthodes de la classe de base sur les types ISerializable
CA2229 : Implémentez des constructeurs de sérialisation
CA2238 : Implémentez les méthodes de sérialisation comme il se doit
CA2235 : Marquez tous les champs non sérialisés
CA2237 : Marquer les types ISerializable avec SerializableAttribute
CA2239 : Spécifiez des méthodes de désérialisation pour les champs facultatifs