ASP.NET MVC 3 List<T> to IEnumerable<SelectListItem>
Solution 1
You could provide callbacks that obtain the key and the value and then use those. Apart from that you can create it as an extension method:
Extension method:
public static List<SelectListItem> ToSelectList<T>(this List<T> Items, Func<T, string> getKey, Func<T, string> getValue, string selectedValue, string noSelection, bool search = false)
{
List<SelectListItem> items = new List<SelectListItem>();
if (search)
{
items.Add(new SelectListItem { Selected = true, Value = "-1", Text = string.Format("-- {0} --", noSelection) });
}
foreach (var item in Items)
{
items.Add(new SelectListItem
{
Text = getKey(item),
Value = getValue(item),
Selected = selectedValue == getValue(item) ? true : false
});
}
return items
.OrderBy(l => l.Text)
.ToList();
}
Usage:
List<Org>() parentOrganisations = // fetch here
model.Organisations = parentOrganisations.ToSelectList(org => org.ID.ToString(),
org => org.OrganisationName,
"-1",
"-- None -- ",
true);
Note: I typed this in the SO-editor, so you might have some syntax errors (they should be easy to solve though).
Solution 2
You can do in controller only like this: -
List<SelectListItem> dropdownItems = parentOrganisations
.Select(item => new SelectListItem
{
Value = item.ID.ToString(),
Text = item.OrganisationName,
Selected = "-1" == item.ID.ToString() ? true : false
})
.ToList();
Paul
A software consultant focusing on all things Microsoft, specifically ASP.NET MVC, SQL Server, Business Intelligence and sometimes dabbling into the murky world of SharePoint. Based in sunny Brisbane, Queensland I'm also a keen (if not pretty awful) golfer and can be found playing anywhere that offers me a good deal.
Updated on June 09, 2022Comments
-
Paul almost 2 years
I'm not currently happy with the way that my DropDownListFor() objects are populated. I'm attempting to find as generic way of populating IEnumerable as possible. This is what I have so far.
Helper:
public static List<SelectListItem> ToSelectList(IDictionary<string,string> dictionaryItems, string selectedValue, string noSelection, bool search = false) { List<SelectListItem> items = new List<SelectListItem>(); if (search) { items.Add(new SelectListItem { Selected = true, Value = "-1", Text = string.Format("-- {0} --", noSelection) }); } foreach (var item in dictionaryItems) { items.Add(new SelectListItem { Text = item.Key, Value = item.Value, Selected = selectedValue == item.Value ? true : false }); } return items .OrderBy(l => l.Text) .ToList(); }
Controller:
[HttpGet] public ActionResult Index() { var model = new CreateModel(); var parentOrganisations = _orgs.FindBy(o => o.OwningOrganisationID == Globals.OrganisationID || o.ID == Globals.OrganisationID) .OrderBy(o => o.OrganisationName); Dictionary<string, string> items = new Dictionary<string, string>(); foreach (var item in parentOrganisations) { items.Add(item.OrganisationName, item.ID.ToString()); } model.Organisations = SelectLists.ToSelectList(items, "-1", "-- None -- ", true); return View(model); }
View:
<div class="control-group"> <label class="control-label">Parent Organisation</label> <div class="controls"> @Html.DropDownListFor(m => m.ParentOrganisationID, Model.Organisations, new { @class = "input-xlarge"}) <p class="help-block">Select a parent organisation to create a branch</p> </div> </div>
There seems to be A LOT of repetitive code in the controller. It takes a generic list, add's the Value and Text to a Dictionary and then uses that as input for a helper which builds up the select list to send as part of the model.
Does anyone have any better ways to achieve this? I hate having bloat in my controller, and when I get several drop downs on a form this is exactly what will happen in this instance.
Thanks,
EDIT - Thanks to Kenneth's helper method, I've now consolidated the whole thing into one call in the controller:
model.Organisations = _orgs.FindBy(o => o.OwningOrganisationID == Globals.OrganisationID || o.ID == Globals.OrganisationID) .OrderBy(o => o.OrganisationName) .ToList() .ToSelectList(org => org.OrganisationName, org => org.ID.ToString(), "-1", "None", true);