how to replace foreach loop with for loop

Question

I am looking for a proper syntax. I am using MVC and in my view I need to loop through the model since I need to do some other things at different counts. I am a novice here and looked through tons of postings but didn't find the syntax. Here is the code, which works:

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.master" Inherits="System.Web.Mvc.ViewPage<IEnumerable<MvcMysurvey.Models.Mysurvey>>" %>
<% foreach (var item in Model) {%>
            <%: Html.HiddenFor(m => item.ID) %>

And here is the code I need the syntax for to make it working:

   <% for (int i = 0; i < Model.Count(); i++) {%>
             <%: Html.HiddenFor(m => m[i].ID) %>

Is it just the "loop count" that you're missing ? Is that why you want to have for loop instead ? By the way, the For loop syntax seems ok to me. What's the problem ? — InspiredBy
– InspiredBy, Commented Jun 14, 2012 at 20:10
Why is it that a foreach isn't what you need? the two are very similar — JK.
– JK., Commented Jun 15, 2012 at 0:36

smartcaveman · Accepted Answer · 2012-06-15 00:31:15Z

5

Your model is of type IEnumerable<MvcMysurvey.Models.Mysurvey>.

The problem is that IEnumerable<T> does not expose an indexer ([]) operator. You have two options for dealing with this inconvenience.

Use an array or a list instead.
Arrays and IList<T> implementations do expose an indexer operator. To use the indexer syntax, you need to convert your model to an array or other IList<T>. So, just change your

<% for (int i = 0; i < Model.Count(); i++) {%>
   <%: Html.HiddenFor(m => m[i].ID) %>

to

<% var items = Model.ToArray();
   for (int i = 0; i < items.Length; i++) {%>
      <%: Html.HiddenFor(m => items[i].ID) %>

Use the the ElementAt method method

While IEnumerable<T> does not expose an indexer operator, there is a LINQ extension method that does the same thing. It is the ElementAt method. To use this syntax, you could change your code to:
```
 <% for (int i = 0; i < Model.Count(); i++) {%>
    <%: Html.HiddenFor(m => m.ElementAt(i).ID) %>
```

The array syntax will be almost certainly be more efficient though.

answered Jun 15, 2012 at 0:31

smartcaveman

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smartcaveman Over a year ago

@user1456934, You can select this answer by clicking the checkbox to the left of my post.

jsmith · Accepted Answer · 2012-06-14 20:16:27Z

0

I think this may be what you're looking for? Your question isn't too clear but it sounds like you're looking to do something based on a condition that the count is equal to something. If that's the case you only need to add an if statement to check the count against whatever value you're looking for.

<% for (int i = 0; i < Model.Count(); i++)
<% { %>
    <% if (i == someCount) %>
    <% { %>
        <!-- Do Something Here -->
    <% } %>
    <%: Html.HiddenFor(m => m[i].ID) %>
<% } %>

answered Jun 14, 2012 at 20:16

jsmith

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1 Comment

user1456934 Over a year ago

this did not work because of IENUMERABLE<T> as explained in the posting above

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