CODEWITHSUNDEEP
c#asp.netasp.net-mvcvariables
nielsv
nielsv

Reputation: 6820

Use variable outside switch statement + asp.net mvc

In my Index Action in my Controller I have this:

public ActionResult Index(string sortOrder)
{
    var model;
    ViewBag.CitySortParm = String.IsNullOrEmpty(sortOrder) ? "City_desc" : "";
    switch (sortOrder)
    {
        case "City_desc":
            model = this.UnitOfWork.AddressRepository.Get().OrderBy(a => a.City);
            break;
    }
    return View(model);
}

This doesn't work, I always get the error: Implicitly-typed local variables must be initialized

Why doesn't this work and how can I fix this?

Upvotes: 1

Views: 1387

Answers (4)

Mauro Cerutti
Mauro Cerutti

Reputation: 684

The first problem is that the type of the model variable cannot be inferred if you just declare it with var model;.

You should explicitly declare its type.

Also, as Jon Skeet correctly pointed out, you must initialize your model somehow before the return... call. Try to imagine what you model's value is if sortOrder is not "City_desc"...

Upvotes: 3

Abbas
Abbas

Reputation: 14432

You have to initialize an implicitly declared variable before using it. A simple example:

var x;

if(true)
    x = "true";

This will get you the same error. This should be hapening:

var x = "";

if(true)
    x = "true";

Same goes for your code. Initialize it before using it. Say your model is of type AddressViewModel, then this should work:

var model = new AddressViewModel();
ViewBag.CitySortParm = String.IsNullOrEmpty(sortOrder) ? "City_desc" : "";
switch (sortOrder)
{
    case "City_desc":
        model = this.UnitOfWork.AddressRepository.Get().OrderBy(a => a.City);
        break;
}
return View(model);

Upvotes: 1

Sriram Sakthivel
Sriram Sakthivel

Reputation: 73492

Implicitly-typed local variables must be initialized

Yes will have to initialize it inline to make it work.

var model = default(MyType);//This should work

Or just declare the type explicitly.

MyType model = default(MyType);//Or null if it is a reference type

Upvotes: 1

Jon Skeet
Jon Skeet

Reputation: 1502106

Why doesn't this work

Two reasons:

  • You're trying to use var without specifying an initial value. You can't do that - the compiler can't infer the type.
  • You're trying to read from the model variable when it may not be initialized - if sortOrder isn't City_desc what would you expect to be returned? And what would that type be?

and how can I fix this?

That depends on what you want to happen if sortOrder isn't City_desc. Work out what value you'd want to return, and make sure it's returned.

Basically, you can't read from a local variable until it's definitely assigned - in other words, until the compiler can prove (by the rules of C#) that by the time you get there, it will have been assigned a value.

In terms of the implicit typing - are you always going to use the same type for your view? If so, just explicitly declare the type of model, as well as fixing the definite assignment part. If not, I'd consider returning within the switch/case statement - I don't think your model local variable is actually helping you much.

Upvotes: 5

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