自定义页面类与自动卸载事件

Question

we have a rather large Silverlight application and we need to add some extra functionality to it. The App consists of an Frame-Element and a TreeView w/ HyperlinkButtons for the navigation. Every content which will be loaded into the main Frame is a Page.

Now, I need to hook into every Page's unload event. Currently we use something like this:

/* PageX.xaml */

<navigation:Page
    x:Class="Foo.Views.PageX" 
    <!-- namespacing -->
    Title="Test Page X"
    Unloaded="Page_Unloaded">

    ...

</navigation:Page>

Code-behind:

/* PageX.xaml.cs */

/* usings */

namespace Foo.Views
{
    public partial class PageX : Page
    {
        public PageX() {
            InitializeComponent();
        }

        private void Page_Unloaded(object sender, RoutedEventArgs e) {
            /* CODE */
        }
    }
}

This approach need to be implemented on each and every Page, as the code within the unloaded method stays exactly the same... As I mentioned earlier, we have a couple of Pages and it would be much more useful to create a custom Page-class where this Page_Unloaded() is implemented directly, so that we don't need to alter every Page.

Can you please tell me how to create such a custom Page-class?

Thanks in advance for any help!!

Kind regards!

Answer 1

You could create a base Page class that all your pages inherit from which registers the event in the constructor...

public class BasePage : Page
{
    public BasePage()
    {
        Unloaded += Page_Unloaded;
    }

    void Page_Unloaded(object sender, RoutedEventArgs e)
    {

    }
}

Then all your pages could inherit from that...

public partial class Page1 : BasePage
{
    public Page1()
    {
        InitializeComponent();
    }
}

...and in the xaml of each page...

<base:BasePage x:Class="WPFApp.Page1"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:base="clr-namespace:WPFApp">

    <Grid>

    </Grid>
</base:BasePage>