var firstTime = false;
var progress

function onSourceDownloadProgressChanged(sender, eventArgs) {
    if (firstTime == false) {
//        var hortGutter = Math.round(document.body.offsetWidth - 850) / 2;
//        var vertGutter = Math.round(document.body.offsetHeight - 420) / 2;
//        sender.findName("LayoutRoot")["Canvas.Left"] = hortGutter;
//        sender.findName("LayoutRoot")["Canvas.Top"] = vertGutter; 
        firstTime = true;
    }

    progress = Math.round((eventArgs.progress * 1000) / 10);
    sender.findName("_progress").Text = progress + "%";
    sender.findName("_progressBar").Width = Math.round((eventArgs.progress * 400));
}