If you request an unbound object from NInject, then the default behaviour is (if a suitable constructor is available) appears to be to create an instance of the appropriate object.
I'd like to disable this behaviour (I had a difficult to debug issue because something was auto-bound instead of picking up my custom binding in a module). This question hints that it is possible, but I'm unable to find the answer from the NInject wiki.
Remove the SelfBindingResolver from the kernel components after creation:
kernel.Components.RemoveAll<IMissingBindingResolver>();
kernel.Components.Add<IMissingBindingResolver, DefaultValueBindingResolver>();
The following is a better, more direct way of removing the SelfBindingResolver, without assuming that the DefaultValueBindingResolver is the only other IMissingBindingResolver component:
kernel.Components.Remove<IMissingBindingResolver, SelfBindingResolver>();
It's possible the Remove<T, TImplementation>() method was only added in a recent version of Ninject, but this works for me using Ninject 3.2.2.0.
Related
I created a new custom Block and wanted to inject an IOptionsSnapshot to read my appsettings.json values. The problem is that I get an error saying there is no parameterless constructor for my custom block.
Is there a way to somehow do this injection or is this a limitation in Piranha and custom blocks.
At the moment neither Fields nor Blocks supports parameter injection into the constructor, however Fields have two initialization methods that both support parameter injection, Init() and InitManager(). Given how models are constructed the easiest solution would probably be to add the corresponding init methods to Blocks as well.
Feel free to open an issue/feature request at the GitHub repo and we can take the discussion from there!
I'm having a frustrating issue with Ninject and MVC 4.
Here is the code block:
Kernel.Bind<IUserInfo>().To<UserInfo().InRequestScope();
var userInfo = Kernel.Get<IUserInfo>();
Most of the time, this is fine, and I have a user info. Sometimes, though, I get the following error:
Error activating IUserInfo
No matching bindings are available, and the Type is not self-bindable.
Activation path:
1) Request for IUserInfo
Suggestions:
1) Ensure that you have defined a binding for IUserInfo.
2) If the binding was defined in a module, ensure that the module has been loaded into the kernel.
3) Ensure you have not accidentally created more than one kernel.
4) If you are using constructor arguments, ensure that the parameter name matches the constructors parameter name.\r\n 5) If you are using automatic module loading, ensure the search path and filters are correct.
I've pared down everything I cant think to, and am at a loss. I don't know why this would fail intermittently. Based on my admittedly limited knowledge of Ninject, there should be no way for the binding to be missing.
I see a lot of references to using the Ninject MVC Nuget packages, but the app as I inherited it does not use those, it initializes Ninject using an ActionFilter. Is this pattern just broken at its core, and somehow interfering with proper binding?
Help?
Take a look at the BindFilter option
https://github.com/ninject/ninject.web.mvc/wiki/Filter-configurations
There is some sort of caching issue I believe, that makes filters behave differently to controllers. This means that the binding can fail, usually under heavy load, but unpredicatably.
It turns out that newer versions of Ninject need more setup for InRequestScope to work. By removing Ninject entirely, and readding references to Ninject, Ninject.Web.Common, and Ninject.Web.MVC, it added the Ninject.Web.Common.cs file that was neccessary for InRequestScope to work.
Previously, it was actually binding InTransientScope, which meant it would get garbage collected, which is non-deterministic, which explains my intermittent issues. I wish it would have thrown exceptions when i tried to bind InRequestScope, but c'est la vie.
According to the documentation, PreparingEventArgs should have an Instance property, so you can supply an alternative instance instead of the default.
But as far as I can see, that property isn't there. Is it supposed to be there or not?
(I know I can swap the instance in the activating event, but I want to avoid creating an instance if I'll just have to throw it away anyway.)
What version of Autofac are you using?
In the latest source the Instance property is indeed removed. The alternative is to hook on to the Activating event and use the ReplaceInstance method on the ActivatingEventArgs.
I'm engaged in building NServiceBus Gateway handler, and I need to avoid config files so that all configuration is defined inside c# classes. As a result I have to convert the following section to c# code
<GatewayConfig>
<Channels>
<Channel Address="http://localhost:25899/SiteB/" ChannelType="Http" Default="true"/>
</Channels>
</GatewayConfig>
I've found GatewayConfig, ChannelCollection and ChannelConfig in a NServiceBus.Config namespace, but I can not link them together, coz GatewayConfig refers to ChannelCollection, but ChannelCollection has nothing to do with ChannelConfig. Please help
Just create a class implementing IProvideConfiguration of GatewayConfig. That gives you a way to provide your own config. Look at the pubsub sample for the exact details on how to do this.
Well, I've found the way to do it as I installed Reflector and looked into the implementation. There is a ChannelCollection.CreateNewElement() method returning back System.Configuration.ConfigurationElement. NServiceBus overriden the method instantiating ChannelConfig inside it, so all I have to do is to cast ConfigurationElement type to ChannelConfig type which is far from intuitive interface. Looks like this NServiceBus.Config.ChannelCollection is kind of unfinished work, because if you look at other collections like NServiceBus.Config.MessageEndpointMappingCollection you can find there all necessary type-safe methods to work with its child elements NServiceBus.Config.MessageEndpointMapping, so I think NServiceBus team was just lazy to make the same for ChannelCollection.
UPDATE: as CreateNewElement() method is protected, I have to implement my own class inherited from ChannelCollection to make a method adding new ChannelConfig element publicly available
Simple question... I want to use Ninject Interceptors to take care of my NFRs, however alot of my classes require arguments in the constructors. I read that they are looking at allowing constructors with arguments but currently I get an error:
Can not instantiate proxy of class: myClass
Could not find a parameterless constructor.
Parameter name: constructorArguments
I am using version 2.2.1 I think, noticed there is a tagged 2.3 version on the extensions site, but will any of this solve my problems? if not is there any way around this?
2.3 adds support for Interface proxies. This means it will solve the problem for all types that are resolved by interface. It's also planned to add support for classes without default constructor.
But be aware that 2.3 is work in progress. While there aren't any known new problems it is not tested yet against real applications as 2.2 is and interface changes of new stuff can still change. Also InRequestScope support for XML and Conventions has temporarily been disabled.