I can’t insert a Dropdown box in C# . Net Core, is there a type conversion error?

Question

Error:

Runtimebinderexception: Cannot implicitly Convert type 'Object' to 'System.Collections.Generic.Ienumerable<Microsoft.AspNetCore.Mvc.Rendering.Selectlistitem>'. An Explicit Conversion exists (are you Missing a cast?)

The Model:

public IEnumerable<SelectList> Emails { get; set; }

The Controller:

public IActionResult Create()
{
  var mls =
    (from geral in _context.Clientes
      orderby geral.Email
      select new { text = geral.Email, value = geral.Email }).ToList();
   ViewBag.MailList = mls.AsEnumerable();
  return View();
}

The View:

<select asp-for="Emails" asp-items="@ViewBag.MailList"></select>

The error appears in the view, if I send a null object until the empty checkbox appears. I’ve tried every kind of conversion and nothing, someone has some light?

Answer 1

The error happens because the wrong type is being sent to View, make that statement new SelectList and pass the properties as required and upon being sent to your View the type is already correct to be used.

public IActionResult Create()
{
    var mls = (
        from geral in _context.Clientes
        orderby geral.Email
        select new { text = geral.Email, value = geral.Email }
    ).ToList();

   ViewBag.MailList = new SelectList(mls, "value", "text");

   return View();
}

that is, the declaration of the right type and recognised by the code of its View.

^References

• Selectlist Class
• Selectlistitem Class
• Cannot implicitly Convert type 'System.Collections.Generic.List' to 'System.Collections.Generic.Ienumerable'