MVC3 Binding to collection data model - asp.net-mvc-3

Question

My question isn't so much about displaying the data its about collecting changes to the data.
My specific scenario is the need to allow users to delete multiple items from a list. I don't know if i'm even approaching this in a locgical way.
The List is a collection of Private Messages. My view model has strings for To, From, Subject, and a bool for "Delete".
public class PrivateMessagesModel {
public PrivateMessagesModel()
{
PrivateMessages = new List<PrivateMessageReceivedModel>();
}
public List<PrivateMessageReceivedModel> PrivateMessages;
}
public class PrivateMessageReceivedModel
{
[DataType(DataType.Text)]
[Display(Name = "From")]
public string From { get; set; }
[DataType(DataType.Text)]
[Display(Name = "Subject")]
public string Subject { get; set; }
[DataType(DataType.Text)]
[Display(Name = "Message")]
public string Message { get; set; }
[DataType(DataType.Text)]
[Display(Name = "Date")]
public DateTime DateTimeSent { get; set; }
[DataType(DataType.Text)]
[Display(Name = "Delete")]
public bool Delete { get; set; }
}
The code to display looks like this. And works ok.
#
model ScaleRailsOnline.Models.PrivateMessagesModel
#{
ViewBag.Title = "Private Messages";
}
<div id="content">
<div class="content">
<h2>
Private Messages</h2>
#using (Html.BeginForm())
{ <table>
#for (int i = 0; i < Model.PrivateMessages.Count; i++)
{
<tr>
<td>
#Html.CheckBoxFor(m => m.PrivateMessages[i].Delete)
</td>
<td>
#Html.DisplayTextFor(m => m.PrivateMessages[i].From)
</td>
</tr>
}
</table>
<p>
<input type="submit" value="Delete" />
</p>
}
</div>
</div>
The problem is when I check a couple of the check boxes and hit the delete button, i get nothing back in the model.
Again, im sure i'm not approaching this in the right way. Any help would be appreciated.

Answer 1

You need to have a controller associated to the Html.BeginForm where the form will be posted.
eg
<div id="formid">
#using (Html.BeginForm("Index1", "Home", new AjaxOptions { UpdateTargetId = "formid",OnSuccess ="OnSuccess" }, new { id = "TheForm" }))
{
#for (int i = 0; i < Model.PrivateMessages.Count; i++)
{
#Html.CheckBoxFor(m => m.PrivateMessages[i].Delete)
}
<input type="submit" name="name" value="Submit" />
}
</div>
On Controller
public ActionResult Index1(List<PrivateMessageReceivedModel> mod)
{
//Now in the mod you will get the value of the delete checkbox.
}

Answer 2

You have to create a Controller class for your model. Then create method that return ActionResult type. and then create View of the newly created controller method.
Here is a sample code.
Model Class
namespace Mvc3Application1.Models
{
public class PrivateMessage
{
public string From { get; set; }
public string Subject { get; set; }
public string Message { get; set; }
public DateTime DateTimeSent { get; set; }
public bool Delete { get; set; }
}
public class PrivateMessageRepository
{
public List<PrivateMessage> GetPrivateMessages()
{
List<PrivateMessage> myPrivateMessages=new List<PrivateMessage>();
//add list of messages in the object myPrivateMessages
myPrivateMessages.Add(new PrivateMessage { From = "abc#abc.com", Subject = "Subject 1", Message = "Message 1", DateTimeSent = DateTime.Now, Delete = false });
myPrivateMessages.Add(new PrivateMessage { From = "abc1#abc.com", Subject = "Subject 2", Message = "Message 2", DateTimeSent = DateTime.Now, Delete = false });
myPrivateMessages.Add(new PrivateMessage { From = "abc2#abc.com", Subject = "Subject 3", Message = "Message 3", DateTimeSent = DateTime.Now, Delete = false });
myPrivateMessages.Add(new PrivateMessage { From = "abc3#abc.com", Subject = "Subject 4", Message = "Message 4", DateTimeSent = DateTime.Now, Delete = false });
myPrivateMessages.Add(new PrivateMessage { From = "abc4#abc.com", Subject = "Subject 5", Message = "Message 5", DateTimeSent = DateTime.Now, Delete = false });
return myPrivateMessages;
}
}
}
Controller class
namespace Mvc3Application1.Controllers {
public class PrivateMessageController : Controller
{
//
// GET: /PrivateMessage/
// Show all the private messages
public ActionResult ListMessages()
{
return View(new Models.PrivateMessageRepository().GetPrivateMessages());
}
//delete the selected messages and return the collection
[HttpPost]
public ActionResult ListMessages(FormCollection collection)
{
List<Models.PrivateMessage> messages = new Models.PrivateMessageRepository().GetPrivateMessages();//all messages
List<Models.PrivateMessage> cloneMessages = new List<Models.PrivateMessage>();//messages left for deletion
int noOfItems = 0;//no of items deleted
int currentItem = 0;//current item in collection 'messages'
string[] deletedItems = collection[0].Split(',');//return from HTML control collection
for (int i = 0; i < deletedItems.Length; i++)
{
if (bool.Parse(deletedItems[i]) == false)//if checkbox is unchecked
{
cloneMessages.Add(messages[currentItem]);//copy original message in cloneMessages collection
}
else //if checkbox is checked
{
noOfItems++;
i++;
}
currentItem++;
}
ViewBag.Items = noOfItems + " message(s) deleted.";
return View(cloneMessages);
}
} }
View
#model IEnumerable<Mvc3Application1.Models.PrivateMessage>
#{
ViewBag.Title = "Private Messages";
}
<h2>Private Messages</h2>
<div style="color:green;font-weight:bold;">#ViewBag.Items</div>
<br />
#using (Html.BeginForm())
{
<table>
<tr>
<th></th>
<th>
From
</th>
<th>
Subject
</th>
<th>
Message
</th>
<th>
DateTimeSent
</th>
</tr>
#foreach (var item in Model)
{
<tr>
<td>
#Html.CheckBoxFor(modelItem => item.Delete)
</td>
<td>
#Html.DisplayTextFor(modelItem => item.From)
</td>
<td>
#Html.DisplayTextFor(modelItem => item.Subject)
</td>
<td>
#Html.DisplayTextFor(modelItem => item.Message)
</td>
<td>
#Html.DisplayTextFor(modelItem => item.DateTimeSent)
</td>
</tr>
}
</table>
<input type="submit" value="Delete"/>
}