What was MS thinking

[Pete Davis]

Okay, someone tell me I'm making a mistake here:

I need to create my own CurrencyManager class derived from
BindingManagerBase.

As far as I can tell this is impossible to do. The MSDN docs say,
erroneously:

---

Notes to Inheritors: When you inherit from BindingManagerBase, you must
override the following members: AddNew, Count, CancelCurrentEdit, Current,
EndCurrentEdit, GetItemProperties, OnCurrentChanged, Position, RemoveAt,
ResumeBinding, SuspendBinding, and UpdateIsBinding.

---

The problem is there are, I believe, 5 members of BindingManagerBase that
are marked as "internal abstract", despite the fact that the class itself is
marked a public abstract.

As far as I can tell, there's no way to override an internal abstract member
from a class in System.Windows.Forms.

Of course, if I don't override the methods, I get a "myclassname does not
implement inherited abstract member 'membername'"

But if I try to override them, I get: "no suitable method found to override"

WTH? I mean, the documentation makes it sound like you can derive from the
class, but at this point, all evidence is to the contrary.

Any ideas?

Pete

 

[yvinogradov]

They are actually marked 'protected internal abstract', which means you
should be able to override them. The following worked for me:

class test : System.Windows.Forms.BindingManagerBase
{
protected override string GetListName(ArrayList list)
{
return null;
}
}

 

[Pete Davis]

What? You actually compiled that? I find that hard to believe. There are
about 20 abstract methods in BindingManagerBase. It won't compile if you
don't implement them.

And yes, string GetListName(ArrayList list) is protected internal abstract ,
but string GetListName() [with no parameters) is simply internal abstract.

Pete

 

[Pete Davis]

By the way, the methods and properties that are internal abstract an NOT
protected internal abstract are:

BindType.get
DataSource.get
GetListName()
IsBinding.get
SetDataSource(object)

Pete

 

[yvinogradov]

You are right Pete, my bad. Didn't notice that there is another
GetListName to be imlplemented. Well, I guess the fellow programmer
forgot to type 'protected' for those two methods and three properties.

 

[Michael S]

Pete, I think MS owes you an icecream, or a MSDN subscription... or both =)

- Michael S

 

[Pete Davis]

Thanks guys. Really, I was kind of hoping someone was going to embarrass me
by saying, "No, all you have to do is XYZ." In fact, for a second, I thought
the other guy had me.

Alas, I'm going to have to write my own BindingManagerBase (or include the
functionality in my CurrencyManager) as well which is a big annoyance since
I already have to write CurrencyManager and RelatedCurrencyManager classes.

I know I can call internal or private methods using reflection. I was kind
of hoping someone might have some way of tricking the compiler into letting
me override internal abstract methods, but I figured that was a real long
shot.

Oh well. Thanks for the responses guys, even though the only solution is to
beat up some .NET framework developers. ;-)

Pete

 

[Steve McLellan]

Hi,

Commiserations, and you might want to consider filing it as a bug report so
others more fortunate than yourself can be spared the torment either in .NET
2.0 or maybe even as part of a framework service pack.

Steve

 

[Michael S]

Hi,

Commiserations, and you might want to consider filing it as a bug report
so others more fortunate than yourself can be spared the torment either in
.NET 2.0 or maybe even as part of a framework service pack.

This is the sad part with .NET.

In Delphi you get all the code for the whole VCL (i.e FCL) and a bug like
this could have been fixed by yourself in no-time flat.There is still the
hazzle of bug-reporting, but you could fix it and move on. It's no fun
telling your project lead or customer that the project is in a dead end
because of a bug in a core library. - Sorry, but if you have the cash, you
could always buy Microsoft and have the bug fixed quicker.. =)

However, there are plenty of Microsoft employees that scans this group and
maybe they'll report the bug.If Microsoft was smart, they should hire Jon
Skeet for a fair amount of money and have him make bug reports, he reads
just about everything in this newsgroup!

And I still think Microsoft owes Pete an icecream... =)

- Michael S