通过

SerializationInfo.GetValue 方法

  • 项目

从 SerializationInfo 存储区中检索一个值。

**命名空间:**System.Runtime.Serialization
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
Public Function GetValue ( _
    name As String, _
    type As Type _
) As Object
用法
Dim instance As SerializationInfo
Dim name As String
Dim type As Type
Dim returnValue As Object

returnValue = instance.GetValue(name, type)

public Object GetValue (
    string name,
    Type type
)

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

public Object GetValue (
    String name, 
    Type type
)

public function GetValue (
    name : String, 
    type : Type
) : Object

参数

  • name
    与要检索的值关联的名称。

返回值

与 name 关联的指定 Type 的对象。

异常

异常类型 条件

ArgumentNullException

name 或 type 为 空引用（在 Visual Basic 中为 Nothing）。

InvalidCastException

与 name 关联的值不能转换为 type。

SerializationException

当前实例中没有找到具有指定名称的元素。

备注

如果存储在 SerializationInfo 中的数据属于所请求的类型（或者是其派生类之一），则直接返回该值。否则，会调用 IFormatterConverter.Convert 来将其转换为适当的类型。

由 GetValue 方法返回的值始终可以安全地转换为在 type 参数中指定的类型。

示例

下面的代码示例演示 GetValue 方法的用法：

' A serializable LinkedList example.  For the full LinkedList implementation
' see the Serialization sample in the .NET Framework SDK.
<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

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

   public static void Main() {}

   Node m_head = null;
   Node m_tail = null;
   
   // Serializes the object.
   [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
   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
   [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)]
   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 in the .NET Framework SDK.
[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 in the.NET Framework SDK.

/** @attribute Serializable()
 */

class LinkedList implements ISerializable
{
    public static void main(String[] args)
    {
    } //main
 
    private Node m_head = null;
    private Node m_tail = null;

    // Serializes the object.
   /** @attribute SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)
    */
    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());
    } // GetObjectData

    // Constructor that is called automatically during deserialization.
    // Reconstructs the object from the information in SerializationInfo info
   /** @attribute SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter=true)
    */
    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())));
    } //LinkedList
} //LinkedList

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

SerializationInfo 类
SerializationInfo 成员
System.Runtime.Serialization 命名空间