windows phone - opening a html file using webBrowser

1:        IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication();  
2:        if (isoStore.FileExists(mHtmlFilename))  
3:        {  
4:          Uri fileUri;  
5:          fileUri = new Uri(mHtmlFilename, UriKind.Relative);  
6:          webBrowser.Navigate(fileUri);  
7:        }