ASP.NET MVC 3中的下拉列表

Question

I am new to MVC so probably confused . can somebody please explain me the dropdown in razor.my questions are-

• What is the difference in dropdownlist and dropdownlistfor
• how do i Pass ID column of my database table as value and NAME column as text.
• How do i add "other" to the dropdownlist.
• how do i access the selectedlistitem in code behind.

if possible please explain with an example.

Answer 1

1. DropDownList is generated by code like this:

    @Html.DropDownList("PersonId", new SelectList(Model.People, "Id", "Text"); 

   On the other hand, DropDownListFor is generated like this:

    @Html.DropDownListFor(m => m.PersonId, new SelectList(Model.People, "Id", "Text") 

   Problem with DropDownList is that it has a magic string and if you decide to refactor the model later on, there's a high change you'll forget to change the magic string too.

2. You could do a LINQ query like this:

    var datalist = New SelectList(from x in _peopleService select new SelectListItem { Text = x.Name, Value = x.Id}); 

   If you don't have a service or an ORM between it you need to apply it to your situation, but you can generate a list like that.

3. After nr 2, you can

    datalist.Add(new SelectListItem() { Text = "Other", Value = "-1"}); 

   Also you have to put that datalist in your viewmodel/model that is passed to the View, so you can generate a selectlist item with that. In this case you could just do:

    @Html.DropDownListFor(x => x.PersonId, Model.PersonList); 

   if you stored the list as PersonList in Model.

4. In your Viewmodel (Well, model in mvc) you have a property where the selected item will be stored, look at the 1st question - In this instance the selected item's id will be stored in the PersonId property.