ASP.NET MVC: How to display strongly typed view model, containing list of items, which also contain
- by Sam Delaney
Hi, I'm building an app using ASP.NET MVC which I want to use a strongly type view model, which contains a List called items which contains an id int and itemName string. The view model also conatins a List called people, and the Person class contains a List.
The way I want to display the information is as a table, with each row having a column of Person name, then n number of columns which contain checkboxes, one for each of the List, and checked based on whether the Person's List (called items) contains the id of the Item.
I have the display working fine, but I'm struggling to understand how to name the items so that the posted method can read the data.
This is what I have in the BeginForm:
<table cellpadding="20">
<thead>
<th>Person name</th>
<!-- for each of the items, create a column with the item name -->
<% foreach( var i in Model.items ) { %>
<th><%= Html.Encode(i.itemName) %></th>
<% } %>
</thead>
<% foreach( var p in Model.people ) { %>
<tr>
<td><%= Html.Encode(p.name) %></td>
<!-- for each item, create a column with a checkbox -->
<% foreach( var i in Model.items ) { %>
<td>
<% if( p.items.Contains(i.id) ) { %>
<!-- vm is the name of the view model passed to the view -->
<%= Html.CheckBox( "vm.people[" + p.id + "].items[" + i.id + "]", true ) %>
<% } else { %>
<%= Html.CheckBox( "vm.people[" + p.id + "].items[" + i.id + "]", false ) %>
<% } %>
</td>
<% } %>
</tr>
<% } %>
</table>
And this code displays the information perfectly. When I click submit, however, I get an Object Reference Not Set.. error message.
Can anyone help with this please?
