Security Exception
<UserControl x:Class='SilverlightApplication3.MainPage' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' xmlns:d='http://schemas.microsoft.com/expression/blend/2008' xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006' mc:Ignorable='d' d:DesignWidth='640' d:DesignHeight='480'> <Grid Height="379" Width="361"> </Grid> </UserControl> //File:Window.xaml.cs using System; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.IO; namespace SilverlightApplication3 { public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); StreamWriter SW; SW = File.CreateText("c:\\s.txt"); SW.WriteLine("A!"); SW.WriteLine("B"); SW.Close(); } } }