Accessing Ninject Kernel.Get() from HttpHandler with existing custom base
I have an ASP.Net webforms app, that uses Ninject 2.2.0.0
I have a HTTPHandler that inherits from the Microsoft.Web.ImageHandler class.
Within it i need to access an instance of a service class that i created.
because i cannot inherit from Ninject.Web.HttpHandlerBase i thought i would just expose the Kernel as a property on the Global.asax class...
protected override IKernel CreateKernel()
{
IKernel kernel = new StandardKernel(new DefaultModule());
var sms = kernel.Get<SiteMapService>();
SiteMapSvc = sms;
Kernel = kernel;
return kernel;
}
public IKernel Kernel
{
get; set;
}
and use the kernel.Get method to obtain the service..
var global = (Global) HttpContext.Current.ApplicationInstance;
var service = global.Kernel.Get<PhotoService>();
This fails with the following...
[ArgumentNullException: Cannot be null
Parameter name: root]
Ninject.ResolutionExtensions.GetResolutionIterator(IResolutionRoot root, Type service, Func`2 constraint, IEnumerable`1 parameters, Boolean isOptional, Boolean isUnique) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionEx开发者_如何学Ctensions.cs:258
Ninject.ResolutionExtensions.Get(IResolutionRoot root, Type service, IParameter[] parameters) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionExtensions.cs:151
Thumb.GenerateImage(NameValueCollection parameters) in \Thumb.ashx.cs:40
UPDATE: I managed to fix this by modifying the Global.Kernel property to this, but now im getting into anti pattern territory...
public IKernel Kernel
{
get { return this.CreateKernel(); }
}
Will now read up and see what this means..
This is using the Service-Locator anti-pattern. It will work, but you lose the flexibility of IoC and add a dependency everywhere that is difficult to test.
This simple answer is that you can add "KernelContainer.Inject(this)" to your HttpHandler. Or you can create a custom module (or modify the existing Ninject.Web one) to do injection before handler execution.
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