In MVC3/.NET4.0/VS2010 web application, selecting a default value for an extension method -
DropDownList
or
DropDownListFor
is tricky.
The
DropDownList
first parameter should be any valid name other than the list instance name.
For example, you can have
DropDownList("xyz",...)
not
DropDownList("CompaniesRef",...)
, for the below example, when
Model.CompaniesRef
instance is used to populate the list.
Same rule applies to
DropDownListFor()
method too. For
DropDownListFor(m=>m.Name,..)
, make sure the "
m.Name
" (actually
Name
) is any
public
"
string
" property in
Model
class.
See the example below:
PersonView.cshtml
<table>
@model MyTestApp.Models.PersonAddressModel
<tr>
<!--
<td>@Html.DropDownList("CompaniesRef", new SelectList(
Model.CompaniesRef,"Key","Value","HP"))
</td>
<td>@Html.DropDownListFor(m=>m.CompaniesRef, new SelectList(
Model.CompaniesRef,"Key","Value","HP"))
</td>
<!--
<td>@Html.DropDownList("CompaniesRef_", new SelectList(
Model.CompaniesRef,"Key","Value","HP"))
</td>
<td>@Html.DropDownListFor(m=>m.Name, new SelectList(
Model.CompaniesRef,"Key","Value","HP"))
</td>
</tr>
</table>
Model class
class Person
{
public KeyValuePair<string, string>[] CompaniesRef { get; set; }
public string Name {get;set;}
public void Load()
{
CompaniesRef = new KeyValuePair<string, string>[]
{
new KeyValuePair<string, string>("MSFT", "Microsoft"),
new KeyValuePair<string, string>("IBM", "IBM"),
new KeyValuePair<string, string>("HP", "HP"),
new KeyValuePair<string, string>("GOOG", "Google"),
new KeyValuePair<string, string>("BOA", "BANK OF AMERICA"),
new KeyValuePair<string, string>("AMC", "American Airlines")
};
}
}
Controller method
public class PersonController : Controller
{
public ActionResult Person(Person p)
{
p.Load();
return View("PersonView",p);
}
}
Started as C++ developer later fell in love with .NET and moved to .NET. I still use Notepad to type in C# console apps. for learning unknown areas. The software business areas I worked are diversified - Gas, Truck Leasing, Telecom, many State and Federal projects.