9.2 Arguments

The Arguments class

The Arguments class is used by Windsor to pass arguments down the invocation pipeline. The class is a simple implementation of non-generic IDictionary, but it has some useful capabilities.

:information_source: Custom IDictionary is respected: When you call container.Resolve passing your own custom implementation of IDictionary Windsor will respect that and not replace it with Arguments. It is advised that you use Arguments though.

Constructors

The class has several constructors:

namedArgumentsAsAnonymousType

You can pass named arguments as properties on anonymous type:

new Arguments(new { logLevel = LogLevel.High });

:information_source: Named arguments are not case sensitive: You can specify logLevel, LogLevel or even LOGLEVEL as property name. All named arguments are matched in case insensitive manner so in all cases the behavior will be the same.

Array of typedArguments

When you don't care about names of the dependencies you can pass them as array, in which case they will be matched by their type.

new Arguments(new[] { LogLevel.High });

:information_source: Typed arguments are matched exactly: When you don't specify type of the dependency it's exact type will be used. So if you pass for example MemoryStream Windsor will try to match it to dependency of type MemoryStream, but not of the base type Stream. If you want to match it to Stream use Insert extension method.

Custom dictionary of arguments

You can also pass already populated dictionary to Arguments in which case its values will be copied over.

Insert extension method

In addition to Arguments class there's also Insert extension method that extends IDictionary. It has several overloads that let you fluently insert values into the dictionary.

args.Insert<Stream>(someMemoryStream)
   .Insert("name", someNamedArgument)
   .Insert(new[] { multiple, typed, arguments})
   .Insert(new { multiple = typed, arguments = also});

:information_source: Insert overwrites: When item under given key already exists Insert will overwrite it.