LabelFor() in a foreach

Question

I have a view with a strongly-typed model associated with it

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master"
                  Inherits="System.Web.Mvc.ViewPage<SomeNamespace.SomeViewModel>" %>

The SomeViewModel looks like this

class SomeViewModel
{
    public IEnumerable<Foo> Foos {get; set;}
}

and say Foo is

class Foo
{
   public string Bar {get; set;}
}

and in the view

<% foreach (var item in Model.Foos) { %>
    <tr>
        <td>
            <%= Html.LabelFor(f => f.Bar) %>
        </td>

I'm not sure how to display Bar property in item using Html.LabelFor()

Can someone help me with this?

Thanks,

@AndyC I don't know how to get at Bar for the loop variable `item`. f => f.[No Bar here. only Foos]` — Professor Chaos, Sep 16 '11 at 13:40
@TheOtherGuy, most examples i've seen have hard coded the labels as table headers and then done the for each after. Are you displaying yours in a table? is there a reason you need the label in your foreach (it will just constantly repeat your label for every row) — Manatherin, Sep 16 '11 at 13:47
@Manatherin I have a collection of Foo objects and i'm trying to display the Bar property for each Foo in each table row. — Professor Chaos, Sep 16 '11 at 13:52

Dismissile · Answer 1 · 2011-09-16T14:19:36.483

48

Do this instead:

<% foreach (var item in Model.Foos) { %>      
<tr>          
    <td>              
        <%= Html.LabelFor(f => item.Bar) %>          
    </td>
<% } %>

Instead of f => f.Bar do f => item.Bar, where item is the name of the variable in your foreach loop.

Here is the much more beautiful razor syntax :)

@foreach( var item in Model.Foos ) {
<tr>
    <td>
        @Html.LabelFor(f => item.Bar)
    </td>
    <td>
        @Html.DisplayFor(f => item.Bar)
    </td>
</tr>
}

edited Sep 16 '11 at 14:19

answered Sep 16 '11 at 14:09

Dismissile

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That is awesome. Not sure the how and why though. An explanation of the need for the mismatch would be helpful for the noobs. – Snekse May 15 '14 at 20:43
Related question: How do I do this and have `TextBoxFor` produce a different ID for each item so I can update properly? – Snekse May 15 '14 at 20:47
Im not sure why this isnt the accepted answer. – Donald Sep 22 '21 at 14:20

Bob Vale · Accepted Answer · 2011-09-16T13:54:40.323

2

have you tried

<% for (var i=0; i<Model.Foos.Count();i++) { %> 
    <tr> 
        <td> 
            <%= Html.LabelFor(f => f.Foos[i].Bar) %> 
        </td>

The LabelFor extension uses a lamda expression to go from your Model object to the selected property, consider f a substituion variable for your model. So you need a way to get from your model to your chosen property. You are telling LabelFor, create a local variable called f and assign it with the value of your model. then use the bit after the => to determine the target property.

If you are desperate to use the foreach, you would have to have a way of translating item back to a property of the original model, (e.g. for an array as Gledrius said x=>x.Foos[Model.Foos.IndexOf(foo)])

failing that if you just want the text value

use '<%= item %>' instead of the whole labelfor or if you have ASP.NET 4 and MVC2 or better use <%: item %> for that HTML encoding goodness

edited Sep 16 '11 at 13:54

answered Sep 16 '11 at 13:44

Bob Vale

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I will try this but is it not possible to use `foreach` ? – Professor Chaos Sep 16 '11 at 13:45
1

LabelFor takes an expression as a parameter so you can't pass it an object (so you can't pass it your item variable). – AndrewC Sep 16 '11 at 13:47
2

You asked for a foreach example and I provided one that works but then you accepted the answer that doesn't use foreach. o_O – Dismissile Sep 16 '11 at 14:56
A downside of this approach is that you end up with multiple ` – Richard Ev Aug 19 '12 at 11:14

score 2 · Answer 3 · answered Sep 16 '11 at 15:26

You could also just write a custom extension that's not tied directly to the Model of the page.

   public static MvcHtmlString LabelForItem<T, V>(this HtmlHelper html, T obj, Expression<Func<T, V>> expression) 
   {
       Func<T,V> func = expression.Compile();
       V val = func(obj);
       return html.Label(val.ToString());
   }

And you'd use it, like this:

@foreach (Foo foo in Model)
{
    <p>
       @(Html.LabelForItem<Foo, string>(foo, f => f.Name))
    </p>
}

score 0 · Answer 4 · edited May 23 '17 at 11:46

0

From here, looks like you need to specify the DisplayName on the property:

[DisplayName("My Bar")]
public string Bar { get; set; }

edited May 23 '17 at 11:46

Community

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answered Sep 16 '11 at 13:34

SwDevMan81

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That's not what he's asking for. – SLaks Sep 16 '11 at 13:41
The problem is, I don't know how to go about specifying the property Bar. Is it `f => f.Bar`(doesn't compile) or `item => item.Bar` (doesn't compile either) – Professor Chaos Sep 16 '11 at 13:42
@TheOtherGuy - How about `Html.LabelFor(x => item.Bar)` – SwDevMan81 Sep 16 '11 at 14:16

Giedrius · Answer 5 · 2011-09-16T13:45:40.287

0

if Foos would be list, it would look like this:

Html.LabelFor(x=>x.Foos[Model.Foos.IndexOf(item)])

edited Sep 16 '11 at 13:45

answered Sep 16 '11 at 13:37

Giedrius

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score 0 · Answer 6 · answered Sep 16 '11 at 13:42

0

You are iterating over your Foo's but not using the item variable at all.

answered Sep 16 '11 at 13:42

AndrewC

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How do i use `item` ? when i do `item => item.Bar`, I get `A parameter named item cannot be declared in this scope ... ` – Professor Chaos Sep 16 '11 at 13:43

LabelFor() in a foreach

6 Answers6