How to bind the ASP.NET drop down list DataTextField property to a nested property

Question

I want to bind the DataTextField property of a ASP.NET drop down control to a property of an object that is a property of the initial data source. How would I accomplish that particular task.

Drop down data source data schema

public class A
{
   public string ID { get; set; }
   public B { get; set; }
} 

public class B
{
   public string Name { get; set; }  //want to bind the DataTextField to this property
}

ASP.NET code behind

DropDownList MyDropDownList = new DropDownList();
List<A> MyList = GetList();

MyDropDownList.DataSource = MyList;
MyDropDownList.DataValueField = "ID";

Answer 1

Say you have a List of A, and want A.ID to be the ID field, and A.B.Name to be the Name field, you cannot bind to B.Name directly, so you either have to create a new property on A to pull the name out of the B property of A or you can use Linq to create an anonymous type that does it for you like this:

List<A> ListA = new List<A>{
    new A{ID="1",Item = new B{Name="Val1"}},
    new A{ID="2", Item =  new B{Name="Val2"}} ,          
    new A{ID="3", Item =  new B{Name="Val3"}}};

DropDownList1.DataTextField = "Name";
DropDownList1.DataValueField = "ID";
DropDownList1.DataSource = from a in ListA
                           select new { ID, Name = a.Item.Name };