OnDeserializedAttribute クラス
アセンブリ: mscorlib (mscorlib.dll 内)
構文
<AttributeUsageAttribute(AttributeTargets.Method, Inherited:=False)> _ <ComVisibleAttribute(True)> _ Public NotInheritable Class OnDeserializedAttribute Inherits Attribute
[AttributeUsageAttribute(AttributeTargets.Method, Inherited=false)] [ComVisibleAttribute(true)] public sealed class OnDeserializedAttribute : Attribute
[AttributeUsageAttribute(AttributeTargets::Method, Inherited=false)] [ComVisibleAttribute(true)] public ref class OnDeserializedAttribute sealed : public Attribute
OnDeserializedAttribute は、オブジェクトを逆シリアル化した後、グラフが返される前に、逆シリアル化したオブジェクトの値を修正する必要があるときに使用します。この属性は、IDeserializationCallback インターフェイスの代わりに使用できます。
OnDeserializedAttribute を使用するには、メソッドに StreamingContext パラメータが含まれている必要があります。この属性により、メソッドがシリアル化インフラストラクチャによって呼び出されるようマークされます。また StreamingContext には、実行されるシリアル化のタイプに関する追加のデータが含まれています。次のコードは、その使用法を示しています。
\\ C# [OnDeserializedAttribute()] private void RunThisMethod(StreamingContext context) { // Code not shown. } ' Visual Basic <OnDeserializedAttribute()> _ Private Sub RunThisMethod(context As StreamingContext) ' Code not shown. End Sub
メモ |
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コードでは、OnDeserializedAttribute の代わりに OnDeserialized という短い語を使用できます。 |
次の例では、OnDeserializedAttribute、OnSerializingAttribute、OnSerializedAttribute、および OnDeserializingAttribute の各属性を、クラス内のメソッドに適用しています。
Imports System Imports System.IO Imports System.Runtime.Serialization Imports System.Runtime.Serialization.Formatters.Binary Public Class Test Public Shared Sub Main() ' Create a new TestSimpleObject object. Dim obj As New TestSimpleObject() Console.WriteLine(vbLf + " Before serialization the object contains: ") obj.Print() ' Open a file and serialize the object into binary format. Dim stream As Stream = File.Open("DataFile.dat", FileMode.Create) Dim formatter As New BinaryFormatter() Try formatter.Serialize(stream, obj) ' Print the object again to see the effect of the 'OnSerializedAttribute. Console.WriteLine(vbLf + " After serialization the object contains: ") obj.Print() ' Set the original variable to null. obj = Nothing stream.Close() ' Open the file "data.xml" and deserialize the object from it. stream = File.Open("DataFile.dat", FileMode.Open) ' Deserialize the object from the data file. obj = CType(formatter.Deserialize(stream), TestSimpleObject) Console.WriteLine(vbLf + " After deserialization the object contains: ") obj.Print() Catch se As SerializationException Console.WriteLine("Failed to serialize. Reason: " + se.Message) Throw Catch exc As Exception Console.WriteLine("An exception occurred. Reason: " + exc.Message) Throw Finally stream.Close() obj = Nothing formatter = Nothing End Try End Sub End Class ' This is the object that will be serialized and deserialized. <Serializable()> _ Public Class TestSimpleObject ' This member is serialized and deserialized with no change. Public member1 As Integer ' The value of this field is set and reset during and ' after serialization. Private member2 As String ' This field is not serialized. The OnDeserializedAttribute ' is used to set the member value after serialization. <NonSerialized()> _ Public member3 As String ' This field is set to null, but populated after deserialization. Private member4 As String ' Constructor for the class. Public Sub New() member1 = 11 member2 = "Hello World!" member3 = "This is a nonserialized value" member4 = Nothing End Sub Public Sub Print() Console.WriteLine("member1 = '{0}'", member1) Console.WriteLine("member2 = '{0}'", member2) Console.WriteLine("member3 = '{0}'", member3) Console.WriteLine("member4 = '{0}'", member4) End Sub <OnSerializing()> _ Friend Sub OnSerializingMethod(ByVal context As StreamingContext) member2 = "This value went into the data file during serialization." End Sub <OnSerialized()> _ Friend Sub OnSerializedMethod(ByVal context As StreamingContext) member2 = "This value was reset after serialization." End Sub <OnDeserializing()> _ Friend Sub OnDeserializingMethod(ByVal context As StreamingContext) member3 = "This value was set during deserialization" End Sub <OnDeserialized()> _ Friend Sub OnDeserializedMethod(ByVal context As StreamingContext) member4 = "This value was set after deserialization." End Sub End Class ' Output: ' Before serialization the object contains: ' member1 = '11' ' member2 = 'Hello World!' ' member3 = 'This is a nonserialized value' ' member4 = '' ' ' After serialization the object contains: ' member1 = '11' ' member2 = 'This value was reset after serialization.' ' member3 = 'This is a nonserialized value' ' member4 = '' ' ' After deserialization the object contains: ' member1 = '11' ' member2 = 'This value went into the data file during serialization.' ' member3 = 'This value was set during deserialization' ' member4 = 'This value was set after deserialization.'
using System; using System.IO; using System.Runtime.Serialization; using System.Runtime.Serialization.Formatters.Binary; public class Test { public static void Main() { // Create a new TestSimpleObject object. TestSimpleObject obj = new TestSimpleObject(); Console.WriteLine("\n Before serialization the object contains: "); obj.Print(); // Open a file and serialize the object into binary format. Stream stream = File.Open("DataFile.dat", FileMode.Create); BinaryFormatter formatter = new BinaryFormatter(); try { formatter.Serialize(stream, obj); // Print the object again to see the effect of the //OnSerializedAttribute. Console.WriteLine("\n After serialization the object contains: "); obj.Print(); // Set the original variable to null. obj = null; stream.Close(); // Open the file "data.xml" and deserialize the object from it. stream = File.Open("DataFile.dat", FileMode.Open); // Deserialize the object from the data file. obj = (TestSimpleObject)formatter.Deserialize(stream); Console.WriteLine("\n After deserialization the object contains: "); obj.Print(); } catch (SerializationException se) { Console.WriteLine("Failed to serialize. Reason: " + se.Message); throw; } catch (Exception exc) { Console.WriteLine("An exception occurred. Reason: " + exc.Message); throw; } finally { stream.Close(); obj = null; formatter = null; } } } // This is the object that will be serialized and deserialized. [Serializable()] public class TestSimpleObject { // This member is serialized and deserialized with no change. public int member1; // The value of this field is set and reset during and // after serialization. private string member2; // This field is not serialized. The OnDeserializedAttribute // is used to set the member value after serialization. [NonSerialized()] public string member3; // This field is set to null, but populated after deserialization. private string member4; // Constructor for the class. public TestSimpleObject() { member1 = 11; member2 = "Hello World!"; member3 = "This is a nonserialized value"; member4 = null; } public void Print() { Console.WriteLine("member1 = '{0}'", member1); Console.WriteLine("member2 = '{0}'", member2); Console.WriteLine("member3 = '{0}'", member3); Console.WriteLine("member4 = '{0}'", member4); } [OnSerializing()] internal void OnSerializingMethod(StreamingContext context) { member2 = "This value went into the data file during serialization."; } [OnSerialized()] internal void OnSerializedMethod(StreamingContext context) { member2 = "This value was reset after serialization."; } [OnDeserializing()] internal void OnDeserializingMethod(StreamingContext context) { member3 = "This value was set during deserialization"; } [OnDeserialized()] internal void OnDeserializedMethod(StreamingContext context) { member4 = "This value was set after deserialization."; } } // Output: // Before serialization the object contains: // member1 = '11' // member2 = 'Hello World!' // member3 = 'This is a nonserialized value' // member4 = '' // // After serialization the object contains: // member1 = '11' // member2 = 'This value was reset after serialization.' // member3 = 'This is a nonserialized value' // member4 = '' // // After deserialization the object contains: // member1 = '11' // member2 = 'This value went into the data file during serialization.' // member3 = 'This value was set during deserialization' // member4 = 'This value was set after deserialization.'
System.Attribute
System.Runtime.Serialization.OnDeserializedAttribute
プラットフォーム
Windows 98, Windows 2000 SP4, Windows Millennium Edition, 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。
参照
- OnDeserializedAttribute クラスのページへのリンク