asp.web表单中的简单注入器用户自定义控件

Question

I follow official guide to use simple injector to inject object in web form and it works, but now i cant make it works in custon control

this is what i do:

public partial class GestioneAttivita_cnStruttureSocieta : System.Web.UI.UserControl
{
    [Import]
    public IUnitOfWork iuow { get; set; }

    public Domain.Entity.Attivita attivitaGestita {get; set;}

    protected void Page_Load(object sender, EventArgs e)
    {
        using (iuow)
        {       
            attivitaGestita = iuow.Attivita.Read(attivitaGestita.IdAttivita);
        }
   }

}

but i get null reference exception since iuow is null

i try to edit global.asax to manage UserControl in this way:

private static void RegisterWebPages(Container container)
        {
            var pageTypes =
                from assembly in BuildManager.GetReferencedAssemblies().Cast<Assembly>()
                where !assembly.IsDynamic
                where !assembly.GlobalAssemblyCache
                from type in assembly.GetExportedTypes()
                where (type.IsSubclassOf(typeof(Page)) **|| type.IsSubclassOf(typeof(UserControl)))**                       
                where !type.IsAbstract && !type.IsGenericType
                select type;

            foreach (Type type in pageTypes)
            {
                var registration = Lifestyle.Transient.CreateRegistration(type, container);
                registration.SuppressDiagnosticWarning(
                    DiagnosticType.DisposableTransientComponent,
                    "ASP.NET creates and disposes page classes for us.");
                container.AddRegistration(type, registration);
            }
        }
    }

         class ImportAttributePropertySelectionBehavior : IPropertySelectionBehavior {
            public bool SelectProperty(Type serviceType, PropertyInfo propertyInfo) {
                // Makes use of the System.ComponentModel.Composition assembly

                bool _return = false;

                _return = (typeof(Page).IsAssignableFrom(serviceType) &&
                    propertyInfo.GetCustomAttributes<ImportAttribute>().Any())
                    **||
                    (typeof(UserControl).IsAssignableFrom(serviceType) &&
                    propertyInfo.GetCustomAttributes<ImportAttribute>().Any());**

                return _return;
            }
        }

but i get same error

is this doable?

Answer 1

To be able to get this working, you will have to hook onto the PreLoad event of the page during initialization. During PreLoad you can walk the page's control hierarchy and initialize all controls like you do with the page itself.

There's actually example code in the Simple Injector repository (that never made it to an official package) that shows you how to do this. Take a look here .