CODEWITHSUNDEEP
jqueryasp.net-mvcrazor
HelloWorld
HelloWorld

Reputation: 4892

ListBoxFor with single selection in asp.net mvc

I am using latest MVC5. I want to use a ListBox NOT a DropDown. The decision which control to use is not single/multiple selection decision.

Thats the error I get:

An exception of type 'System.InvalidOperationException' occurred in System.Web.Mvc.dll but was not handled in user code

Additional information: The parameter 'expression' must evaluate to an IEnumerable when multiple selection is allowed.

@using (Html.BeginForm())
{
   // @Html.ValidationMessageFor(model => model.)
    @Html.ListBoxFor(x => x.SelectedCompanyId, new SelectList(Model.Companies, "CompanyId", "Address"), new { @id = "CompanyListBox" })
}

But how can I remove the multiple selection? jQuery does not help here as the razor exception is first raised before the document is ready:

$(document).ready(function () {
    debugger;
    $("#CompanyListBox").removeAttr('multiple');
});

Upvotes: 1

Views: 9603

Answers (2)

Darin Dimitrov
Darin Dimitrov

Reputation: 1039438

You can only use the ListBoxFor helper with IEnumerable<T> properties. In your example, if SelectedCompanyId is not an IEnumerable<T> it simply won't work. The ListBoxFor helper is designed to be used for multiple selections. Also if you remove the multiple="multiple" attribute using javascript, it's the same as if you were using a DropDownListFor helper.

Upvotes: 3

SlightlyMoist
SlightlyMoist

Reputation: 882

One way is to use a DropDownListFor and set the "size" attribute to be the number of visible items you want.

For example 

@Html.DropdownListFor(x => x.SelectedCompanyId, new SelectList(Model.Companies, "CompanyId", "Address"), new { @id = "CompanyListBox", @size=10 })

Will display a "listbox" with 10 visible items.

Upvotes: 4

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