Design Pattern (maybe)

[csharpula csharp]

Hello,
I got the following scenario :
ComboBox in UI where the user chooses one of the options and according
to his/her choise - I create new object (or sub form). What is the best
way doing it? (I can do switch with cases but it seems not good enough)
Thanks!

 

[Marc Gravell]

If this is four options that are known at compile-time, then switch
should be fine. If you need the same code repeatedly, and the 4
options share some commonality (base-class or interface) then perhaps
make a factory method that accepts an enum and returns the common-
factor, i.e.

static IFoo CreateFoo(FooType type) // an enum
{
switch(type) {
case type.SimpleFoo: return new SimpleFoo();
...
default: throw new ArgumentException("type");
}
}

If the types aren't known in advance (i.e. it comes from a database),
then you'd need a factory approach, perhaps with reflection
(Type.GetType(name) and/or Activator.CreateInstance()) - but this is
slower and more complex.

But keep it simple if you can - it will be easier to debug, which is
worth a lot.

 

[Nicholas Paldino [.NET/C# MVP]]

In this case, I would recommend a class factory pattern:

http://en.wikipedia.org/wiki/Factory_method_pattern

 

[Christof Nordiek]

Hello,
I got the following scenario :
ComboBox in UI where the user chooses one of the options and according
to his/her choise - I create new object (or sub form). What is the best
way doing it? (I can do switch with cases but it seems not good enough)
Thanks!

It depends on the rules wich etnries should be shown in the DropDown and
wich form should be opend when.
In the easy case of a fixed (not to large) set of entries and each opens a
certain form I'd say switch is OK.

In other cases: It depends

But it should also be considered how the list/rules my change in future.
(Maintainability)

Christof