Can someone point me to an article that shows the dropdownlist being populated from linq to sql (text and value being set).
Thanks Danny
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4 Answers
Now that the HtmlHelper extension takes an IEnumerable<SelectListItem>, I don't create SelectList's, but usually just create the SelectListItems with LINQ.
Controller
ViewData["CategoryID"] = categories.Select( c => new SelectListItem
{
Text = c.CategoryName,
Value = c.CategoryID
}
);
View
<%= Html.DropDownList("CategoryID") %>
or if I want a default selection
<%= Html.DropDownList("CategoryID",
(IEnumerable<SelectListItem>)ViewData["CategoryID"],
"Select a Category" ) %>
EDIT:
The interesting bit about the dropdown list is that you need to supply a range of values from which to select a single value that fits into your actual data model. I typically provide the range (menu items) via view data and expect back the model values when the page is posted. If you wanted strongly-typed menus as well, you'd need to provide a view-only model that encapulates your real model and any menus. This would involve, on posting, the use of prefixes to identify the model elements. The trade-off, to my mind, is simpler model binding on post vs. the use of strongly-typed menus in the view. I'm not hung up on the latter, so I opt not to put my menus in the model. If you wanted to do this, though, it might look like the following.
Model
public class CategoryViewModel
{
public Category Category { get; set; }
public IEnumerable<SelectListItem> CategoryMenu { get; set; }
...
}
Controller
Display action
var model = new CategoryViewModel();
model.CategoryMenu = categories.Select( c => new SelectListItem
{
Text = c.CategoryName,
Value = c.CategoryID
}
);
...
return View(model);
Create action
[AcceptVerbs( HttpVerbs.Post )]
public ActionResult Create( [Bind(Prefix="Category")]Category category )
{
...
}
View
<%= Html.TextBox("Category.Name") %>
<%= Html.DropDownList("Category.CategoryID",
Model.CategoryMenu,
"Select a Category" ) %>
1 Comment
Danny
Thats great. Could you provide an example using this with the ViewModel pattern. Thanks
Here's one great article by Rob Connery
Controller Code
NorthwindDataContext db = new NorthwindDataContext();
var categories = from c in db.Categories select c;
ViewData["CategoryID"] = new SelectList(categories, "CategoryID", "CategoryName");
View Markup
<%=Html.DropDownList("CategoryID")%>
1 Comment
Çağdaş Tekin
You don't need the second argument in the html helper. The method will look that up for you if you just pass the "CategoryID".
If you need to add html attributes to your tags this would be a way of doing it. Pass a Model to your View e.i. "return View(someModel)" then in the View:
<select id="Groups" name="Groups">
<% foreach (SelectListItem item in Model.GroupsDropDown)
{
if (item.Selected)
{%>
<option selected="selected" title="<%= item.Text %>">
<%= item.Text%></option>
<%}
else
{%>
<option title="<%= item.Text %>">
<%= item.Text%></option>
<%} %>
<% } %>
</select>
GroupsDropDown is a property in your Model like this:
public IEnumerable GroupsDropDown { get; set; }
Comments
Write in the view:
@{
TaskManagerContext context = new TaskManagerContext();
IEnumerable<TestTask1.Models.User> CDrop = context.Users.ToList();
List<SelectListItem> selectList = new List<SelectListItem>();
foreach (var c in CDrop)
{
SelectListItem i = new SelectListItem();
i.Text = c.Username.ToString();
i.Value = c.ID.ToString();
selectList.Add(i);
}
}
You can reference it ike that:
@Html.DropDownListFor(m => m.UserID,
new SelectList(selectList, "Value", "Text"));
You can also choose a specific row:
TaskManagerContext context = new TaskManagerContext();
UsersRepository repo = new UsersRepository();
User user = repo.GetAll().FirstOrDefault(u => u.ID == ViewBag.UserId);
ViewBag.User = user;
<div><h3><label>@ViewBag.Title1</label>@ViewBag.User.Username</h3></div>
