IE10 - how to prevent "Your current security settings do not allow this file to be downloaded" popup from appearing?

WPF WebBrowser is very a limited (yet inextensible, sealed) wrapper around WebBrowser ActiveX control. Fortunately, there's a hack we can use to obtain the underlying ActiveX object (note this may change in the future versions of .NET). Here's how to block a file download:

using System.Reflection;using System.Windows;namespace WpfWbApp{    // By Noseratio (http://stackoverflow.com/users/1768303/noseratio)    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();            this.WB.Loaded += (s, e) =>            {                // get the underlying WebBrowser ActiveX object;                // this code depends on SHDocVw.dll COM interop assembly,                // generate SHDocVw.dll: "tlbimp.exe ieframe.dll",                // and add as a reference to the project                var activeX = this.WB.GetType().InvokeMember("ActiveXInstance",                    BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.NonPublic,                    null, this.WB, new object[] { }) as SHDocVw.WebBrowser;                // now we can handle previously inaccessible WB events                 activeX.FileDownload += activeX_FileDownload;            };            this.Loaded += (s, e) =>            {                this.WB.Navigate("http://technet.microsoft.com/en-us/sysinternals/bb842062");            };        }        void activeX_FileDownload(bool ActiveDocument, ref bool Cancel)        {            Cancel = true;        }    }}

XAML:

<Window x:Class="WpfWbApp.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        Title="MainWindow" Height="350" Width="525">    <WebBrowser Name="WB"/></Window>