Question

This is my Model:

public class MyModel{
 public string Name { get; set; }
 public string listType { get; set; }
 public string SelectedItem { get; set; }
}

I have a partial view:

@model List<MyModel>
@{

SelectListItem iEqualTo = new SelectListItem { Text = "Equel To", Value = "EqualTo" };
SelectListItem iNotEqualTo = new SelectListItem { Text = "Not Equal To", Value = "NotEqualTo" };
SelectListItem iGreaterThan = new SelectListItem { Text = "Greater Than", Value = "GreaterThan" };
SelectListItem iLessThan = new SelectListItem { Text = "Less Than", Value = "LessThan" };
SelectListItem iBetween = new SelectListItem { Text = "Between", Value = "Between" };


List<SelectListItem> MyFirstList = new List<SelectListItem>() {
    iEqualTo, iNotEqualTo, iGreaterThan, iLessThan, iBetween
};

List<SelectListItem> MySecondList = new List<SelectListItem>() {
    iEqualTo, iNotEqualTo
};

}


@foreach(var item in Model) {

  if(item.listType =="Firsttype"){

   <span> @Html.DropDownList(item.Name , MyFirstList) </span>

  } else {

   <span> @Html.DropDownList(item.Name , MySecondList) </span>

  }
}

So I need Selected = true in List<SelectListItem> in DropDownList that item which name equal to MyModel.SelectedItem? what is your suggestion? In actual my view have more SelectListItem and List<SelectListItem> and for some limitations I can’t pass the List<SelectListItem> as my model property and I need to handle it in view. I think to handle it by lambda inline but I don’t know is possible, something like this: @Html.DropDownList(item.Name , MySecondList.each(a=> if (a.ToString() == item.SelectedItem) {a.Selected = true})

Is any way to do this? and if I am wrong to use inline lambda does any other way to handle this?

Answer 1

You can use a SelectList, which has a constructor with an IEnumerable and an Object (selected value).

@Html.DropDownList(item.Name, new SelectList(MyFirstList, item.SelectedItem));

EDIT

I think I faced your problem when trying to use a DropDownList in a loop.

You can try to use this generic extension method (in a static “helper” class)

public static IEnumerable<SelectListItem> ToSelectListItem<T, TValue, TText, TSelectedValue>(this IEnumerable<T> enumerable,
            Func<T, TText> text,
            Func<T, TValue> value,
            TSelectedValue selectedValue)
        {
            return enumerable.Select(item => new SelectListItem
            {
                Text = text(item).ToString(),
                Value = value(item).ToString(),
                Selected = value(item).Equals(selectedValue)
            }).AsEnumerable();
        }

and then

@Html.DropDownList(item.Name, MyFirstList.ToSelectListItem(m => m.Text, m => m.Value, item.SelectedItem)