Question

I am trying to create a form for collecting information about an item. There are two types: default item and special item. The fields of item shows on the form by default.

public class Item
{
   Id
   Name
   Quantity
   Type //default, special
}

public class SpecialItem : Item //inherits from item
{
   //extra fields here
   ExpiryDate
   SafeForChildren
}

How will I take the extra fields of SpecialItem to user.

I think the fields of SpecialItem should not show until the user indicates he wants to add special item by selecting the type.

I think of using a tab to show extra fields
A collapsible control – I don’t if this exists
Hiding the controls and showing them when necessary
Any other idea

Answer 1

If the two class have a clear relation between them and this relation is well comprensible to your user, I think it’s a good thing to show every field.
Put all the fields inside a groupbox and add two option buttons for the Item and SpecialItem class.
By default (at form load) the Item class will be selected and the two extra field are disabled.
If the user choose the SpecialItem class option button, enable the other two fields.

I have seen this behavior in many options dialogs when selecting an option will enable other specific options.