Shawn Larson Shawn Larson - 2 months ago 46
C# Question

How to add item to IEnumerable SelectListItem

I am trying to add an item to an IEnumerable SelectList. I have an initial query that populates my list, I then have a query to check to see if an item called "INFORMATIONAL" exists. If not, I need to add it to the list returned from my initial query. Here is my code. It does not like list.Add(newItem). Any assistance would be appreciated. Thanks

public IEnumerable<SelectListItem> GetCategoriesByAccountID(string AccountID)
{
IEnumerable<SelectListItem> list = null;

using (var context = new AMPEntities())
{
// Queries DB for list of categories by AccountID
var query = (from ca in context.CustomAlerts
where ca.AccountID == AccountID
orderby ca.AlertCategory
select new SelectListItem { Text = ca.AlertCategory, Value = ca.AlertCategory }).Distinct();
list = query.ToList();

// Checks list to see if "INFORMATIONAL" already exists
var item = (from l in list
where l.Value == "INFORMATIONAL"
select new SelectListItem { Text = l.Text, Value = l.Value }).FirstOrDefault();

// If "INFORMATIONAL" is not present add it to list
if (item == null)
{
var newItem = new SelectListItem { Text = "INFORMATIONAL", Value = "INFORMATIONAL" };
list.Add(newItem);
}
}

return list;
}

Answer

The problem is that your variable is of type IEnumerable<SelectListItem>. Either change it to List<SelectListItem> or use another variable.

public IEnumerable<SelectListItem> GetCategoriesByAccountID(string AccountID)
    {
        List<SelectListItem> list = null;

        using (var context = new AMPEntities())
        {
            // Queries DB for list of categories by AccountID
            var query = (from ca in context.CustomAlerts
                        where ca.AccountID == AccountID
                        orderby ca.AlertCategory
                        select new SelectListItem { Text = ca.AlertCategory, Value = ca.AlertCategory }).Distinct();
            list = query.ToList();

            // Checks list to see if "INFORMATIONAL" already exists
            var item = (from l in list
                        where l.Value == "INFORMATIONAL"
                        select new SelectListItem { Text = l.Text, Value = l.Value }).FirstOrDefault();

            // If "INFORMATIONAL" is not present add it to list
            if (item == null)
            {
                var newItem = new SelectListItem { Text = "INFORMATIONAL", Value = "INFORMATIONAL" };
                list.Add(newItem);
            }
        }

        return list;
    }