using Silverlight 3's HtmlPage.Window.Navigate method to reuse an already open browser window

Question

I want to use an external browser window to implement a preview functionality in a silverlight application. There is a list of items and whenever the user clicks one of these items, it's opened in a separate browser window (the content is a pdf document, which is why it is handled ouside of the SL app).

Now, to achieve this, I simply use

HtmlPage.Window.Navigate(new Uri("http://www.bing.com"), "_blank");

which works fine.

Now my client doesn't like the fact that every click opens up a new browser window. He would like to see the browser window reused every time an item is clicked. So I went out and tried implementing this:

Option 1 - Use the overload of the Navigate method, like so:

HtmlPage.Window.Navigate(new Uri("http://www.bing.com"), "foo");

I was assuming that the window would be reused when the same target parameter value (foo) would be used in subsequent calls.
This does not work. I get a new window every time.

Option 2 - Use the PopupWindow method on the HtmlPage

HtmlPage.PopupWindow(new Uri("http://www.bing.com"), "blah", new HtmlPopupWindowOptions());

This does not work. I get a new window every time.

Option 3 - Get a handle to the opened window and reuse that in subsequent calls

private HtmlWindow window;
private void navigationButton_Click(object sender, RoutedEventArgs e)
{
    if (window == null)
        window = HtmlPage.Window.Navigate(new Uri("http://www.bing.com"), "blah");
    else
        window.Navigate(new Uri("http://www.bing.com"), "blah");

    if (window == null)
        MessageBox.Show("it's null");
}

This does not work. I tried the same for the PopupWindow() method and the window is null every time, so a new window is opened on every click. I have checked both the EnableHtmlAccess and the IsPopupWindowAllowed properties, and they return true, as they should.

Option 4 - Use Eval method to execute some custom javascript

private const string javascript = @"var popup = window.open('', 'blah') ; 
                                    if(popup.location != 'http://www.bing.com' ){
                                        popup.location = 'http://www.bing.com';
                                    }
                                    popup.focus();";

private void navigationButton_Click(object sender, RoutedEventArgs e)
{
    HtmlPage.Window.Eval(javascript);
}

This does not work. I get a new window every time.

option 5 - Use CreateInstance to run some custom javascript on the page

private void navigationButton_Click(object sender, RoutedEventArgs e)
{
    HtmlPage.Window.CreateInstance("thisIsPlainHell");
}

and in my aspx I have

function thisIsPlainHell() {
    var popup = window.open('http://www.bing.com', 'blah');
}

This doesn't work. I get a new window every time.

Am I doing something wrong? I'm definitely no javascript expert, so I'm hoping it's something obvious I'm missing here.

Cheers, Phil

Answer 1

This is a security feature of the browser. The re-use of named windows is limited to the domain of the document current being displayed by that window.

Your page hosting the Silverlight control will be running from "http://www.yoursite.com" hence it can only re-use window named "foo" if that window is also currently showing content from "http://www.yoursite.com". Since your have loaded "http://www.bing.com" into that window it is no longer visible to code running in the context "http://www.yoursite.com". Hence when you open a window using "Foo" the browser doesn't see a current window with that name and hence creates another one.

Answer 2

Are you sure it isn't a browser setting causing this? I use HtmlPage.Window.Navigate(new Uri(url)) and it always navigates the current tab that my silverlight control is sitting in.

Answer 3

Apparently the problem is that the window.name property is lost when navigating to bing.com. When I navigate to one of my custom pages it seems to be working fine.