CA2238: Implement serialization methods correctly

Applies to: Visual Studio Visual Studio for Mac

Note

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Item	Value
RuleId	CA2238
Category	Microsoft.Usage
Breaking change	Breaking - If the method is visible outside the assembly. Non-breaking - If the method is not visible outside the assembly.

Cause

A method that handles a serialization event does not have the correct signature, return type, or visibility.

Rule description

A method is designated a serialization event handler by applying one of the following serialization event attributes:

• System.Runtime.Serialization.OnSerializingAttribute

• System.Runtime.Serialization.OnSerializedAttribute

• System.Runtime.Serialization.OnDeserializingAttribute

• System.Runtime.Serialization.OnDeserializedAttribute

  Serialization event handlers take a single parameter of type System.Runtime.Serialization.StreamingContext, return void, and have private visibility.

How to fix violations

To fix a violation of this rule, correct the signature, return type, or visibility of the serialization event handler.

When to suppress warnings

Do not suppress a warning from this rule.

Example

The following example shows correctly declared serialization event handlers.

Imports System
Imports System.Runtime.Serialization

Namespace UsageLibrary

   <SerializableAttribute> _ 
   Public Class SerializationEventHandlers

      <OnSerializingAttribute> _ 
      Private Sub OnSerializing(context As StreamingContext) 
      End Sub

      <OnSerializedAttribute> _ 
      Private Sub OnSerialized(context As StreamingContext) 
      End Sub

      <OnDeserializingAttribute> _ 
      Private Sub OnDeserializing(context As StreamingContext)
      End Sub

      <OnDeserializedAttribute> _ 
      Private Sub OnDeserialized(context As StreamingContext)
      End Sub

   End Class

End Namespace

using System;
using System.Runtime.Serialization;

namespace UsageLibrary
{
   [SerializableAttribute]
   public class SerializationEventHandlers
   {
      [OnSerializingAttribute]
      void OnSerializing(StreamingContext context) {}

      [OnSerializedAttribute]
      void OnSerialized(StreamingContext context) {}

      [OnDeserializingAttribute]
      void OnDeserializing(StreamingContext context) {}

      [OnDeserializedAttribute]
      void OnDeserialized(StreamingContext context) {}
   }
}

Related rules

CA2236: Call base class methods on ISerializable types

CA2240: Implement ISerializable correctly

CA2229: Implement serialization constructors

CA2235: Mark all non-serializable fields

CA2237: Mark ISerializable types with SerializableAttribute

CA2239: Provide deserialization methods for optional fields

CA2120: Secure serialization constructors