Forum› Xamarin.Forms
Instantiate Extension class in XAML with constructor injection
joacar
USMember ✭✭
USMember ✭✭
Hi,
I have created a LocalizeExtension to use in XAML (xmlns:i18n="clr-namespace:OrderCentral.Helpers;assembly=OrderCentral") and it uses a constructror that expects an instance of ILocalize. Everything is registered with the dependency injection service (AutoFac) but it fails to properly locate the ILocalize when to instantiate LocalizeExtension. Resolving the dependency directly from the container works so it has been registered.
How is the correct way of doing this?
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You can't call non-default constructors from XAML. Typically a XAML-friendly class will have a default constructor and then use public properties to configure them.
@Adam, you can instantiate objects with non-default constructor with
<x:Arguments>. Also described in Charles book chapter.@joacar, I found not very practical to make constructor injection for the MVVM-helpers (because they a not generally portable, no XAML-friendly etc) and personally go for Locator pattern if I need take them via DI-container. It is dumb, but easy and works. You also can add additional constructor that accept your dependencies for easer unit-testing if you want to test it.
You just blew my mind...
@ylemsoul
That is awesome.
@ylemosul That was how I ended up solving it. Will read the link to Charle's book - thanks for that!
@ylemsoul Can you provide a simple example of utilization?