ISecurityEncodable.FromXml(SecurityElement) 方法

定义

命名空间:

System.Security

程序集:

System.Runtime.dll

通过 XML 编码重新构造具有指定状态的安全对象。

public:
 void FromXml(System::Security::SecurityElement ^ e);

public void FromXml (System.Security.SecurityElement e);

abstract member FromXml : System.Security.SecurityElement -> unit

Public Sub FromXml (e As SecurityElement)

参数

e

SecurityElement

用于重新构造安全对象的 XML 编码。

示例

下面的代码示例演示如何实现 FromXml 方法。 此代码示例是为 ISecurityEncodable 类提供的一个更大示例的一部分。

    // Populate the permission's fields from XML.
public:
    virtual void FromXml(SecurityElement^ element) override
    {
        specifiedAsUnrestricted = false;
        stateFlags = (SoundPermissionState)0;

        // If XML indicates an unrestricted permission, 
        // make this permission unrestricted.
        String^ attributeString = 
            (String^) element->Attributes["Unrestricted"];
        if (attributeString != nullptr)
        {
            specifiedAsUnrestricted = Convert::ToBoolean(attributeString);
            if (specifiedAsUnrestricted)
            {
                stateFlags = SoundPermissionState::PlayAnySound;
            }
        }

        // If XML indicates a restricted permission, parse the flags.
        if (!specifiedAsUnrestricted)
        {
            attributeString = (String^) element->Attributes["Flags"];
            if (attributeString != nullptr)
            {
                stateFlags = (SoundPermissionState) Convert::ToInt32(
                    Enum::Parse(SoundPermissionState::typeid, 
                    attributeString, true));
            }
        }
    }

// Populate the permission's fields from XML.
public override void FromXml(SecurityElement e)
{
    m_specifiedAsUnrestricted = false;
    m_flags = 0;

    // If XML indicates an unrestricted permission, make this permission unrestricted.
    String s = (String)e.Attributes["Unrestricted"];
    if (s != null)
    {
        m_specifiedAsUnrestricted = Convert.ToBoolean(s);
        if (m_specifiedAsUnrestricted)
            m_flags = SoundPermissionState.PlayAnySound;
    }

    // If XML indicates a restricted permission, parse the flags.
    if (!m_specifiedAsUnrestricted)
    {
        s = (String)e.Attributes["Flags"];
        if (s != null)
        {
            m_flags = (SoundPermissionState)
            Convert.ToInt32(Enum.Parse(typeof(SoundPermission), s, true));
        }
    }
}

' Populate the permission's fields from XML.
Public Overrides Sub FromXml(ByVal e As SecurityElement)
    m_specifiedAsUnrestricted = False
    m_flags = 0

    ' If XML indicates an unrestricted permission, make this permission unrestricted.
    Dim s As String = CStr(e.Attributes("Unrestricted"))
    If Not (s Is Nothing) Then
        m_specifiedAsUnrestricted = Convert.ToBoolean(s)
        If m_specifiedAsUnrestricted Then
            m_flags = SoundPermissionState.PlayAnySound
        End If
    End If
    ' If XML indicates a restricted permission, parse the flags.
    If Not m_specifiedAsUnrestricted Then
        s = CStr(e.Attributes("Flags"))
        If Not (s Is Nothing) Then
            m_flags = CType(Convert.ToInt32([Enum].Parse(GetType(SoundPermission), s, True)), SoundPermissionState)
        End If
    End If

End Sub

注解

扩展安全对象的自定义代码需要实现 ToXml 和 FromXml 方法，以使对象具有安全性。