SerializationInfo.GetValue(String, Type) 方法

定義

命名空間:

System.Runtime.Serialization

組件:

System.Runtime.dll

組件:

System.Runtime.Serialization.Formatters.dll

組件:

mscorlib.dll

組件:

netstandard.dll

從 SerializationInfo 存放區擷取值。

public:
 System::Object ^ GetValue(System::String ^ name, Type ^ type);

public object? GetValue (string name, Type type);

public object GetValue (string name, Type type);

member this.GetValue : string * Type -> obj

Public Function GetValue (name As String, type As Type) As Object

參數

name

String

與要擷取的值相關聯的名稱。

type

Type

要擷取之值的 Type。 如果儲存的值無法轉換為這個型別，則系統將擲回 InvalidCastException。

傳回

Object

指定的 Type 的物件與 name 相關聯。

例外狀況

ArgumentNullException

name 或 type 為 null。

InvalidCastException

與 name 相關聯的數值無法轉換為 type。

SerializationException

在目前的執行個體中找不到具有指定名稱的項目。

範例

下列程式碼範例示範如何使用 GetValue 方法：

// A serializable LinkedList example.  For the full LinkedList implementation
// see the Serialization sample.
[Serializable]
ref class LinkedList: public ISerializable
{
private:
   Node^ m_head;
   Node^ m_tail;

   // Serializes the object.
public:
   virtual void GetObjectData( SerializationInfo^ info, StreamingContext /*context*/ )
   {
      // Stores the m_head and m_tail references in the SerializationInfo info.
      info->AddValue( "head", m_head, m_head->GetType() );
      info->AddValue( "tail", m_tail, m_tail->GetType() );
   }

   // Constructor that is called automatically during deserialization.
private:
   // Reconstructs the object from the information in SerializationInfo info
   LinkedList( SerializationInfo^ info, StreamingContext /*context*/ )
   {
      Node^ temp = gcnew Node( 0 );
      // Retrieves the values of Type temp.GetType() from SerializationInfo info
      m_head = dynamic_cast<Node^>(info->GetValue( "head", temp->GetType() ));
      m_tail = dynamic_cast<Node^>(info->GetValue( "tail", temp->GetType() ));
   }
};

// A serializable LinkedList example.  For the full LinkedList implementation
// see the Serialization sample.
[Serializable()]
class LinkedList: ISerializable {

   public static void Main() {}

   Node m_head = null;
   Node m_tail = null;

   // Serializes the object.
   public void GetObjectData(SerializationInfo info, StreamingContext context){
      // Stores the m_head and m_tail references in the SerializationInfo info.
      info.AddValue("head", m_head, m_head.GetType());
      info.AddValue("tail", m_tail, m_tail.GetType());
   }

   // Constructor that is called automatically during deserialization.
   // Reconstructs the object from the information in SerializationInfo info
   private LinkedList(SerializationInfo info, StreamingContext context)
   {
      Node temp = new Node(0);
      // Retrieves the values of Type temp.GetType() from SerializationInfo info
      m_head = (Node)info.GetValue("head", temp.GetType());
      m_tail = (Node)info.GetValue("tail", temp.GetType());
   }
}

' A serializable LinkedList example.  For the full LinkedList implementation
' see the Serialization sample.
<Serializable()> Class LinkedList
    Implements ISerializable

    Public Shared Sub Main()
    End Sub

    Private m_head As Node = Nothing
    Private m_tail As Node = Nothing    
    
    ' Serializes the object.
    Public Sub GetObjectData(info As SerializationInfo, _
    context As StreamingContext) Implements ISerializable.GetObjectData
    
        ' Stores the m_head and m_tail references in the SerializationInfo info.
        info.AddValue("head", m_head, m_head.GetType())
        info.AddValue("tail", m_tail, m_tail.GetType())
    End Sub
    
    
    ' Constructor that is called automatically during deserialization.
    ' Reconstructs the object from the information in SerializationInfo info.
    Private Sub New(info As SerializationInfo, context As StreamingContext)
        Dim temp As New Node(0)
        ' Retrieves the values of Type temp.GetType() from SerializationInfo info.
        m_head = CType(info.GetValue("head", temp.GetType()), Node)
        m_tail = CType(info.GetValue("tail", temp.GetType()), Node)
    End Sub
End Class

備註

如果 儲存在 中的資料 SerializationInfo 屬於所要求的類型 (或其其中一個衍生類別) ，則會直接傳回該值。 否則會 IFormatterConverter.Convert 呼叫 ，將它轉換成適當的類型。

方法傳 GetValue 回的值一律可以安全地轉換成 參數中指定的 type 型別。