C# DnsPermission 類別應用範例（二）：Copy 複製權限、Intersect 交集判斷、ToXML 序列化與 Demand 執行安全性檢查

Intersect 交集判斷

private void button8_Click(object sender, EventArgs e)
{
    try
    {
        button6.PerformClick(); // 觸發 button6 建立 myPermission
        DnsPermission copy = (DnsPermission)myPermission.Copy();
        DnsPermission none = new DnsPermission(PermissionState.None);
        none.Demand();
        DnsPermission intersect = (DnsPermission)copy.Intersect(none);
        if (intersect != null)
            PrintKeysAndValues(intersect.ToXml().Attributes);
        else
            MessageBox.Show("交集權限不存在");
    }
    catch (Exception ex) { MessageBox.Show(ex.Message); }
}

UseDns 顯示目前權限 XML

public void UseDns()
{
    button6.PerformClick();
    myPermission.Demand();
    PrintKeysAndValues(myPermission.ToXml().Attributes);
}
private void PrintKeysAndValues(Hashtable ht)
{
    IDictionaryEnumerator en = ht.GetEnumerator();
    while (en.MoveNext())
    {
        listBox1.Items.Add(en.Key);
        listBox2.Items.Add(en.Value);
    }
}

示範 Copy、Intersect、ToXml、Demand 組合使用，驗證 DNS 存取權限交集與序列化。