CODEWITHSUNDEEP
c#visual-studio-2010ninject
Callum Linington
Callum Linington

Reputation: 14417

Ninject Form Clarification

I have a ModuleLoader : NinjectModule which is where I bind everything.

Firstly I use

Bind<Form>().To<Main>();

to Bind a System.Windows.Forms.Form to my Main form.

Is this correct?

Secondly in the Program.cs I use this:

 _mainKernel = new StandardKernel(new ModuleLoader());
 var form = _mainKernel.Get<Main>();

Where _mainKernel is a ninject standard kernel.

Then I use Application.Run(form)

Is this correct?

I'm unsure as to what to bind together when it comes to Windows.Forms.

Thanks for any help.

Upvotes: 0

Views: 428

Answers (1)

Adam Rodger
Adam Rodger

Reputation: 3562

You shouldn't really be binding to System.Windows.Forms.Form. Ninject is primarily meant for binding interfaces to concrete types so that you can pass around dependencies as interfaces and switch out the concrete implementation at runtime/during tests.

If you just want to use Ninject to create your Form in this way though, you'd simply use Bind<MyForm>().ToSelf() then do kernel.Get<MyForm>(). If you are requesting the concrete type directly though and it doesn't take any dependencies, there's not much point in using Ninject to initialise it.

In your situation, if your form implements an interface then you would do: Bind<IMainForm>().To<MainForm>() and request the interface type from Ninject. Usually your interface shouldn't be bound to the concept of a "form" though, it should be agnostic of the implementation (so later you could produce a CLI and website version and simply swap the Ninject bindings).

You could use the Model-View-Presenter design pattern (or a variant) to achieve this like:

public interface IUserView
{
    string FirstName { get; }
    string LastName { get; }
}

public class UserForm : IUserView, Form
{
    //initialise all your Form controls here

    public string FirstName
    {
        get { return this.txtFirstName.Text; }
    }

    public string LastName
    {
        get { return this.txtLastName.Text; }
    }
}

public class UserController
{
    private readonly IUserView view;

    public UserController(IUserView view)
    {
        this.view = view;
    }

    public void DoSomething()
    {
        Console.WriteLine("{0} {1}", view.FirstName, view.LastName);
    }
}

Bind<IUserView>().To<UserForm>();
Bind<UserController>().ToSelf();

//will inject a UserForm automatically, in the MVP pattern the view would inject itself though    
UserController uc = kernel.Get<UserController>(); 
uc.DoSomething();

Upvotes: 1

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