CODEWITHSUNDEEP
c#asp.netasp.net-mvclinq
John John
John John

Reputation: 1

How to Create an Empty SelectList

I have the folloiwng action method:

public JsonResult LoadSitesByCustomerName(string customername)
{
    var customerlist = repository.GetSDOrg(customername)
                                 .OrderBy(a => a.NAME)
                                 .ToList();
    var CustomerData;
    CustomerData = customerlist.Select(m => new SelectListItem()
    {
        Text = m.NAME,
        Value = m.NAME.ToString(),
    });
    return Json(CustomerData, JsonRequestBehavior.AllowGet);
}

but currently i got the following error on var CustomerData;:

implicitly typed local variables must be initialized

so i am not sure how i can create an empty SelectList to assign it to the var variable ? Thanks

Upvotes: 16

Views: 22710

Answers (6)

Lapenkov Vladimir
Lapenkov Vladimir

Reputation: 3218

Use this to create an empty SelectList:

new SelectList(Enumerable.Empty<SelectListItem>())

Enumerable.Empty<SelectListItem>() creates an empty sequences which will be passed to the constructor of SelectList. This is neccessary because SelectList has no constructor overloading without parameters.

Upvotes: 36

Christos
Christos

Reputation: 53958

You could try this one:

IEnumerable<SelectListItem> customerList = new List<SelectListItem>();

The error you were getting is reasonable, since

The var keyword instructs the compiler to infer the type of the variable from the expression on the right side of the initialization statement.

On the other hand, you could try the following one:

var customerList = customerlist.Select(m => new SelectListItem()
                   {
                       Text = m.NAME,
                       Value = m.NAME.ToString(),
                   });

The reason why the second assignment will work is that in this way the compiler can infer the type of the variable, since it knows the type of the LINQ query returns.

Upvotes: 11

user4584103
user4584103

Reputation:

empty list item with default one 

var area = new[] { new tbl_Area { AreaID = -1, AreaName = "Please Select Main Area" } };

tbl_Area can be a class or datamodel

 class tbl_Area{
      public int AreaID {get;set;}
      public string AreaName {get;set;}
 }

Upvotes: 1

David Grant
David Grant

Reputation: 41

Try this:

customerlist = new[] { new SelectListItem { } };

Upvotes: 4

frikinside
frikinside

Reputation: 1244

That error means that you cannot declare a var variable without giving a value, for example:

var double1 = 0.0; // Correct, compiler know what type double1 is.
var double2; // Error, compiler not know what type double2 is.

You need to assign a value to var CustomerData; for example:

var CustomerData = customerlist.Select(m => new SelectListItem()
            {
                Text = m.NAME,
                Value = m.NAME.ToString(),

            });

Upvotes: 4

Andy Jones
Andy Jones

Reputation: 604

Initialise the variable when you declare it:

var CustomerData = customerlist.Select(m => new SelectListItem()
{
    Text = m.NAME,
    Value = m.NAME.ToString(),
});

Upvotes: 2

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