webBrowserView.FileDialog += new FileDialogHandler(webBrowserView_FileDialog);

private static void webBrowserView_FileDialog(object sender, FileDialogEventArgs e)
{
    System.Windows.Forms.OpenFileDialog dialog = new System.Windows.Forms.OpenFileDialog();

    dialog.Filter = "All Files (*.*)|*.*|All Supported Types (*.apk;*.ipa;*.appx)|*.apk;*.ipa;*.appx|apk file (*.apk)|*.apk|Apple Device Application File (*.ipa)|*.ipa|*.appx|*.appx";
    dialog.FilterIndex = 2;
    dialog.RestoreDirectory = true;
    dialog.FileName = e.DefaultFileName;

    var res = dialog.ShowDialog();
    if (res == DialogResult.OK)
        e.Continue(dialog.FileName);
    else if (res == DialogResult.Cancel)
        e.Cancel();

    e.Handled = true;
}