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Mark ISerializable types with serializable







Breaking Change


An externally visible type implements the System.Runtime.Serialization.ISerializable interface and the type is not marked with the System.SerializableAttribute attribute. The rule ignores derived types whose base type is not serializable.

To be recognized by the common language runtime as serializable, types must be marked with the SerializableAttribute attribute even if the type uses a custom serialization routine through implementation of the ISerializable interface.

To fix a violation of this rule, apply the SerializableAttribute attribute to the type.

Do not exclude a warning from this rule for exception classes because they must be serializable to work correctly across application domains.

The following example shows a type that violates the rule. Uncomment the SerializableAttribute attribute line to satisfy the rule.

Imports System
Imports System.Runtime.Serialization
Imports System.Security.Permissions

Namespace UsageLibrary

   ' <SerializableAttribute> _ 
   Public Class BaseType
      Implements ISerializable
      Dim baseValue As Integer

      Sub New()
         baseValue = 3
      End Sub

      Protected Sub New( _ 
         info As SerializationInfo, context As StreamingContext)
         baseValue = info.GetInt32("baseValue")

      End Sub

      <SecurityPermissionAttribute(SecurityAction.Demand, _ 
          SerializationFormatter := True)> _ 
      Overridable Sub GetObjectData( _ 
         info As SerializationInfo, context As StreamingContext) _ 
         Implements ISerializable.GetObjectData
         info.AddValue("baseValue", baseValue)

      End Sub

   End Class

End Namespace