Ninject conditional binding based on parameter type

Question

I\'m using a factory to return a datasender:

Bind()
    .ToFactory();

public interface IDataSenderFactory
{
    IDataSender CreateData         


        

Answer 1

After some looking into Ninject source I have found following:

• a.Parameters.Single(b => b.Name == "connection") gives you variable of type IParameter, not real parameter.

• IParameter has method object GetValue(IContext context, ITarget target) that requires not null context parameter (target can be null).

• I have not found any way to get IContext from Request (variable a in your sample).

• Context class does not have parameterless constructor so we can't create new Context.

To make it work you can create dummy IContext implementation like:

public class DummyContext : IContext
{
    public IKernel Kernel { get; private set; }
    public IRequest Request { get; private set; }
    public IBinding Binding { get; private set; }
    public IPlan Plan { get; set; }
    public ICollection<IParameter> Parameters { get; private set; }
    public Type[] GenericArguments { get; private set; }
    public bool HasInferredGenericArguments { get; private set; }
    public IProvider GetProvider() { return null; }
    public object GetScope() { return null; }
    public object Resolve() { return null; }
}

and than use it

kernel.Bind<IDataSender>()
      .To<RemotingDataSender>()
      .When( a => a.Parameters
                   .Single( b => b.Name == "connection" )
                   .GetValue( new DummyContext(), a.Target ) 
               as RemotingConnection != null );

It would be nice if someone could post some info about obtaining Context from inside When()...