CodeAccessPermission.FromXml(SecurityElement) 方法

定义

当在派生类中替代时,用 XML 编码重新构造具有指定状态的安全对象。

public:
 abstract void FromXml(System::Security::SecurityElement ^ elem);
public abstract void FromXml (System.Security.SecurityElement elem);
abstract member FromXml : System.Security.SecurityElement -> unit
Public MustOverride Sub FromXml (elem As SecurityElement)

参数

elem
SecurityElement

用于重新构造安全对象的 XML 编码。

实现

例外

elem 参数为 null

elem 参数不包含与当前实例类型相同的实例的 XML 编码。

不支持 elem 参数的版本号。

示例

下面的代码示例演示 方法的 FromXml 替代。 此代码示例是为 CodeAccessPermission 类提供的一个更大示例的一部分。

public:
   virtual void FromXml( SecurityElement^ e ) override
   {
      // The following code for unrestricted permission is only included as an example for
      // permissions that allow the unrestricted state. It is of no value for this permission.
      String^ elUnrestricted = e->Attribute("Unrestricted");
      if ( nullptr != elUnrestricted )
      {
         m_Unrestricted = Boolean::Parse( elUnrestricted );
         return;
      }

      String^ elName = e->Attribute("Name");
      m_Name = elName == nullptr ? nullptr : elName;
   }
public override void FromXml(SecurityElement e)
 {
     // The following code for unrestricted permission is only included as an example for
     // permissions that allow the unrestricted state. It is of no value for this permission.
     String elUnrestricted = e.Attribute("Unrestricted");
     if (null != elUnrestricted)
     {
         m_Unrestricted = bool.Parse(elUnrestricted);
         return;
     }

     String elName = e.Attribute( "Name" );
     m_Name = elName == null ? null : elName;
 }
Public Overrides Sub FromXml(ByVal e As SecurityElement)
    ' The following code for unrestricted permission is only included as an example for
    ' permissions that allow the unrestricted state. It is of no value for this permission.
    Dim elUnrestricted As String = e.Attribute("Unrestricted")
    If Nothing <> elUnrestricted Then
        m_Unrestricted = Boolean.Parse(elUnrestricted)
        Return
    End If

    Dim elName As String = e.Attribute("Name")
    m_name = IIf(elName Is Nothing, Nothing, elName)
End Sub

注解

扩展安全对象的自定义代码需要实现 ToXmlFromXml 方法,使对象可安全编码。

实施者说明

必须在派生类中重写此方法。

适用于