ASP.NET MVC: Render checkbox list from MultiSelectList
How do you associate a MultiSelectList with a list of checkboxes?
eg. I pass something like this to the model
model.Groups = new MultiSelectList(k.Groups, "Id", "Name", selectedGroups)
How should I render it? This doesn't work
<% foreach (var item in Model.Groups.Items) { %>
<input type="checkbox" name="groups" value="<%=item.Value%>" i开发者_如何学编程d="group<%=item.Value%>" checked="<%=item.Selected?"yes":"no"%>" />
<label for="group<%=item.Value%>"><%=item.Text%></label>
<% } %>
Error CS1061: 'object' does not contain a definition for 'Value'...
Is there a HTML Helper method that I can use?
(Then, unless it is straightforward, how should I then get the selected values back on the Controller when the form is submitted?)
I just tested to see how we can see if the selection was changed.
public class Group {
public int ID { get; set; }
public string Name { get; set; }
}
//And some data to play with
var allGroups = new List<Group>();
allGroups.Add(new Group { ID = 1, Name = "one" });
allGroups.Add(new Group { ID = 2, Name = "two" });
allGroups.Add(new Group { ID = 3, Name = "three" });
var selectedGroups = new List<Group>();
selectedGroups.Add(allGroups[0]);
selectedGroups.Add(allGroups[2]);
var m = new MultiSelectList(allGroups, "ID", "Name",
selectedGroups.Select(x => x.ID));
//passed that data to the view with ViewData
ViewData["list"] = m;
The checkbox elements :
<% foreach (var item in (MultiSelectList)ViewData["list"]) { %>
<input type="checkbox" name="groups" value="<%=item.Value%>"
id="group<%=item.Value%>"
<%=item.Selected ? "checked=\"checked\"" : String.Empty%>/>
<label for="group<%=item.Value%>"><%=item.Text%></label>
<% } %>
Accepted an int array in the action :
[HttpPost]
public ActionResult SomeAction(int[] groups) {
if (groups != null) {
var postedSelection = allGroups.Where(x => groups.Contains(x.ID));
if (!selectedGroups.SequenceEqual(postedSelection)) {
//selection was changed
}
else {
//selection is the same
}
}
else {
//no group ID was posted
}
}
I hope that gives some idea.
I just wanted to share my implementation using the example from above. I'm populating properties that are organized into key / value pairs in my database. In my example I store each property as a key value pair in a Dictionary. Each item in the Dictionary will contain a string key such as "Color" and a MultiSelectList with values like DataValueField="1", DataTextField="Black" etc...
VewModel Code
public Dictionary<string, MultiSelectList> Properties { get; private set; }
private void SetProperties()
{
this.Properties = new Dictionary<string, MultiSelectList>();
foreach(InventoryItemProperty property in new InventoryItemPropertyRepository().FindAllInventoryItemProperties())
{
this.Properties.Add(property.Key.Name, new MultiSelectList(property.Values, "Id", "Value"));
}
}
View markup
<div id="editor-inventory-item-properties">
<% foreach(string key in Model.Properties.Keys){ %>
<div class="editor-label">
<label for="<%= key.ToLower() %>"><%= key %></label><br />
<% foreach(var item in Model.Properties[key]){ %>
<input type="checkbox"
id="<%= key.ToLower() + "-" + item.Text.ToLower() %>"
name="inventoryItemPropertyValues"
value="<%= item.Value %>"
<%= item.Selected ? "checked=\"checked\"" : string.Empty %> />
<label for="<%= key.ToLower() + "-" + item.Text.ToLower() %>">
<%= item.Text %></label><br />
<% } %>
</div>
<% } %>
</div>
Controller Action code
//
// POST: /Admin/InventoryItems/Create
[HttpPost]
public ActionResult Create(InventoryItem inventoryItem, int[] inventoryItemPropertyValues)
{
try
{
inventoryItem.Created = DateTime.Now;
inventoryItem.LastUpdated = inventoryItem.Created;
this.inventoryItemRepository.Add(inventoryItem);
this.inventoryItemRepository.Save();
if(inventoryItemPropertyValues != null)
{
SaveInventoryItemPropertyValues(inventoryItem.Id, inventoryItemPropertyValues);
}
return RedirectToAction("Details", new { id = inventoryItem.Id });
}
catch
{
throw;
//return View();
}
}
private void SaveInventoryItemPropertyValues(int inventoryItemId, int[] inventoryItemPropertyValues)
{
for(int i = 0; i < inventoryItemPropertyValues.Length; i++)
{
this.inventory_Item_ProperytValueRepository.Add(new Inventory_Item_PropertyValue() { InventoryItemId = inventoryItemId, InventoryItemPropertyValueId = inventoryItemPropertyValues[i] });
}
this.inventory_Item_ProperytValueRepository.Save();
}
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