Question

I am having a bit of trouble understanding how I will design a class.

I want to be able to get n amount of System fields out onto a report alongside custom fields.

I want a simple method on an interface called:

ICollection<Field> GetFieldDefinitions();

Internally this should get all the fields that I need to show on the report.

A second method will return field and their values too:

ICollection<Field> GetFieldDefinitionsWithValues(T src);

T is the source of where the information for each field will be populated from, e.g. if I pass in Company, the field definition if it contains CompanyName, I will do a lookup on the Company table and retrieve the info and add it to the field.

public Class SystemFieldCompany
{
    IDictionary<string,Field> list;
    private readonly ValidationEngine _val;
    public SystemFieldCompany(ValidationEngine val)
    {
      _val = val;
      list = new Dictionary<string,Field>();
    }

    public ICollection<Field> GetFields()
    {

     list.add("id",new Field{name = "id", value = "5"});
     list.add("nameofcompany",new Field{name = "nameofcompany", value = "super guys"});      
     return list.Values;   
    }

    //pass in model object with values on it, set up fields, then pass back all fields
    ICollection<Field> GetFieldsWithValues(T object);
}

Should this class above be a concrete class?
e.g. var fields = new FieldClass().GetFields();

or should I use composition? How can I do this via an interface?

Answer 1

Abstract Class is what your after

public abstract class FieldBase
{
ICollection<Field> _data=new List<Field>();

abstract void DoValidationOrSomething();

ICollection<Field> virtual GetFields()  //perform validation internally - return back the object 
{
DoValidationOrSomething();
return _data;
}

T virtual UpdateFields(ICollection<Field> fields);  //pass in model object with values on it, set 
{
_data.Clear();
_data.AddRange(fields);
}
up fields, then pass back all fields
ICollection<Field> virtual GetFieldsWithValues(T object)
{
return _data.Where(f=>f.Name=T);
}
}

then in your concrete

public class SomeTable:FieldBase
{
public void DoValidationOrSomething()
{
//per class validation here
}
}