3 layer architechture and little details like dropdown lists

Question

So I am refactoring a little application as an example to get more practice. The purpose of the application (let's say) is to collect the data from a "sign up new user" form, save it in the database. The only limitation I have is I have to use a special custom Data Access class which communicates directly with the database and returns the data (if applicable) in a DataTable object.

I have a question regarding a little details on a form and how do they fit in into the layer architecture. For example, my form has a drop down list that's fed from the database, but at the same time drop down list doesn't represent an object per SE (unlike a User that is a object, there is a class User that has multiple methods, data members etc). I don't want to have calls to the stored procedure right there in the code behind but I also do not wish to overdo on abstraction.

What would be an elegant way to take care of these little details w/o creating a class abstraction galore.

Hope I am being clear

Answer 1

Funny you should ask that. I went through that issue here.

These other Stack Overflow Questions that I've answered that show other parts (tangentially related):

Getting ListView Data Items from Objects
Working with ListViews
Concatenating Properties in a DropDownList

Answer 2

I don't know what's best practice, but what I do is I have a utility class that has a method that takes as arguments a DropDownList object and an enum, so I do

FillDropDown( ddlistPhoneType, DropDownTypes.PhoneTypes );

The utility class fills the dropdowns sometimes from the database, other times from XML, and occasionally some hardcoded values. But at least the GUI doesn't have to worry about that.

Answer 3

An option for getting non-object data to the UI is to create one or more lookup classes that are a bucket or "service" for getting odd bits of data for things like drop down lists etc...

Example:

myDDL.DataSource = Lookup.GetAllCountries(); // GetAllCountries is a static method
// set name/value fields etc...
myDDL.DataBind();

Using this methodology, you can still support tier separation. It's not object oriented or elegant, but it is very practical.