UML Newbie

I have been trying UML to model my application design for long time. However, I just can't do it *well*. In other words, I don't know how to start, how should I model it for certain situation and etc. I used to read quite alot of online UML related articles and books. They didn't help me much. After thinking for long time, I decided to get my hand dirty by doing modeling as what I think it should be. Of course, I refer some other online resources in order to dot it *correctly*.

Ok, here is my first *offical* class diagram. It shows the classes and relationships between my class controls in a form. It is backward works. It is drawn after I have designed and implemented it. Ya, ya I know I am on the wrong way. But please just ignore it for a moment and look at the UML I have done.


Click to enlarge

May be I should briefly describe class diagram above.

• Item form class is my form.
• Item form has a combobox class (not shown in diagram, should it?), called ComboA.
• ComboA.InteractiveChange() event is binded to a Item form's property, called ItemType.
• ItemTypeBaseInfoCtrl is my custom dynamic control loader. It has a event which binded to Property ItemType. Once the event triggered, it adds derived container class of cntItemTypeBase (such as cntSerial) dynamicly based on options choisen from the value of property ItemType.
• OTOH, oShowIngredient class also has a event binded to property ItemType. It adds/removes page to pageframe and concrete class of cntIngredientBase (such as cntIngredient) into page dynamicly at runtime based on ItemType value either.
• Item Form class has a List object called MultiLocationListObj class which is subclass of class icListObj.

Did my diagram draw correctly? Could anybody give my some advises, with any example? Should I draw diagram for UI layer?

BTW, are there any UML forum?

Thank you.