Calling an internal constructor

[Pete Davis]

I know I can use reflection to call internal, protected, and private methods
in a class, but I need to instantiate an object that is public but has an
internal constructor (The CurrencyManager class).

Is there a way to do this with reflection?

I'm so mad at MS about the CurrencyManager design it makes me want to
scream. It's been causing me headaches for months.

All of this would be easily fixable if I could create my own CurrencyManager
derived from BindingManagerB ase, and though the documentation has a "Note to
inheritors" section, BindingManagerB ase actually has internal virtual
methods, so there's no way to derive from it outside of S.W.F. ARGH.

Pete

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

Re: Calling an internal constructor

Pete,

Unfortunately, there is nothing you can do to call this constructor from
your constructor in code (even through reflection) so that your class can
derive from that class correctly.

I would recommend going to the Product Feedback center and creating an
entry there regarding the issue. I'll definitely vote for it. The Product
Feedback center is located at (watch for line wrap):

http://lab.msdn.microsoft.com/productfeedback/default.aspx

I'll also see what I can do about raising awareness at MS about this
issue.

Hope this helps.

--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard. caspershouse.co m

"Pete Davis" <pdavis68@NOSPA M.hotmail.com> wrote in message
news:ArGdnSPCFr ng3sjfRVn-rg@giganews.com ...[color=blue]
>I know I can use reflection to call internal, protected, and private
>methods
> in a class, but I need to instantiate an object that is public but has an
> internal constructor (The CurrencyManager class).
>
> Is there a way to do this with reflection?
>
> I'm so mad at MS about the CurrencyManager design it makes me want to
> scream. It's been causing me headaches for months.
>
> All of this would be easily fixable if I could create my own
> CurrencyManager
> derived from BindingManagerB ase, and though the documentation has a "Note
> to
> inheritors" section, BindingManagerB ase actually has internal virtual
> methods, so there's no way to derive from it outside of S.W.F. ARGH.
>
> Pete
>
>[/color]

[Pete Davis]

Re: Calling an internal constructor

Which issue? The CurrencyManager one?

Submitted it here:

http://lab.msdn.microsoft.com/productfeedback/viewfeedback.aspx?feedbackid=3507eb9d-00bb-4d86-939f-26d37137cf1a

Their response was "this is by design" because there's no way to "inject"
the new BMB derived class into the BindingContext.

My response was that you can get around the injection problem via
reflection, but the correct fix would be for them to simply provide a method
to do that.

They apparently don't seem to excited about fixing this, though. Because as
well all know, MS has forseen every possible use of their CurrencyManager so
why would anyone need to write their own?

As for creating the CurrencyManager , I found at least two ways to do it (I'm
very stubborn and am very reluctant to take "no" for an answer).

The first is using Activator:

Type cmType = typeof(Currency Manager);
Type[] paramTypes = new Type[1];
paramTypes[0] = typeof(object);
object[] argList = new object[1];
argList[0] = myDataSource;
CultureInfo currCulture = Application.Cur rentCulture;

CurrencyManager cm = (CurrencyManage r) Activator.Creat eInstance(cmTyp e,
BindingFlags.No nPublic | BindingFlags.In stance,
null,
argList,
currCulture,
null);


Optionally, you can replace that last line with:

ConstructorInfo ci = cmType.GetConst ructor(BindingF lags.NonPublic |
BindingFlags.In stance,
null,
paramTypes,
null);
CurrencyManager cm = (CurrencyManage r) ci.Invoke(Bindi ngFlags.NonPubl ic,
null, argList, currCulture);


I didn't realize that invoking the constructor would create an object. I
guess I was thinking back to the old C++ days where to pull something like
this off, you actually had to allocate the object first, then invoke the
constructor.

Anyway, both methods will result in a CurrencyManager .

Now, I need to see if I can do it for a RelatedCurrency Manager which is an
internal type. ARGH...

Thanks for the help Nicolas.

Pete


"Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard .caspershouse.c om> wrote in
message news:%23l8cvA4O FHA.3880@tk2msf tngp13.phx.gbl. ..[color=blue]
> Pete,
>
> Unfortunately, there is nothing you can do to call this constructor[/color]
from[color=blue]
> your constructor in code (even through reflection) so that your class can
> derive from that class correctly.
>
> I would recommend going to the Product Feedback center and creating an
> entry there regarding the issue. I'll definitely vote for it. The[/color]
Product[color=blue]
> Feedback center is located at (watch for line wrap):
>
> http://lab.msdn.microsoft.com/produc...k/default.aspx
>
> I'll also see what I can do about raising awareness at MS about this
> issue.
>
> Hope this helps.
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - mvp@spam.guard. caspershouse.co m
>
> "Pete Davis" <pdavis68@NOSPA M.hotmail.com> wrote in message
> news:ArGdnSPCFr ng3sjfRVn-rg@giganews.com ...[color=green]
> >I know I can use reflection to call internal, protected, and private
> >methods
> > in a class, but I need to instantiate an object that is public but has[/color][/color]
an[color=blue][color=green]
> > internal constructor (The CurrencyManager class).
> >
> > Is there a way to do this with reflection?
> >
> > I'm so mad at MS about the CurrencyManager design it makes me want to
> > scream. It's been causing me headaches for months.
> >
> > All of this would be easily fixable if I could create my own
> > CurrencyManager
> > derived from BindingManagerB ase, and though the documentation has a[/color][/color]
"Note[color=blue][color=green]
> > to
> > inheritors" section, BindingManagerB ase actually has internal virtual
> > methods, so there's no way to derive from it outside of S.W.F. ARGH.
> >
> > Pete
> >
> >[/color]
>
>[/color]

[Pete Davis]

Re: Calling an internal constructor

It took a little trickery, but I managed to also create the
RelatedCurrency Manager.

This is fantastic since this really solves my major problem.

My problem is that I have a custom hierarchical grid control and unlike the
MS DataGrid, this one is really hierarchical in the sense that you can have
multiple parents expanded or collapsed at a given point.

My problem was I needed to traverse the data hierarchy to figure out the
parents and children in the hierarchy. I could have written code to
duplicate what the CurrencyManager does, I suppose, but why re-invent the
wheel? So instead, I create these "shadow" currency managers that aren't in
BindingContext and thus not bound to any controls, but still allow me to
navigate the records without affecting other controls that are bound to the
same data source.

This has been plagueing me for weeks. I kept coming up with different ideas
but nothing was working. My last attempt was pretty extreme. Using
reflection, I got all the currency managers tied to the same data source,
then unbound all controls bound to those currency managers, navigated the
currency managers, then rebound the controls. The problem of course, is that
the controls were still receiving event notifications and there was no way
that I could find to unsubscribe and resubscribe them.

Fortunately, the current method is far cleaner and much faster.

Thanks for the help Nicholas.

Pete

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

Re: Calling an internal constructor

Pete,

I don't think I really did much here, but you are welcome!


--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard. caspershouse.co m

"Pete Davis" <pdavis68@NOSPA M.hotmail.com> wrote in message
news:uJ-dnU4s148J6MjfRV n-jg@giganews.com ...[color=blue]
> It took a little trickery, but I managed to also create the
> RelatedCurrency Manager.
>
> This is fantastic since this really solves my major problem.
>
> My problem is that I have a custom hierarchical grid control and unlike
> the
> MS DataGrid, this one is really hierarchical in the sense that you can
> have
> multiple parents expanded or collapsed at a given point.
>
> My problem was I needed to traverse the data hierarchy to figure out the
> parents and children in the hierarchy. I could have written code to
> duplicate what the CurrencyManager does, I suppose, but why re-invent the
> wheel? So instead, I create these "shadow" currency managers that aren't
> in
> BindingContext and thus not bound to any controls, but still allow me to
> navigate the records without affecting other controls that are bound to
> the
> same data source.
>
> This has been plagueing me for weeks. I kept coming up with different
> ideas
> but nothing was working. My last attempt was pretty extreme. Using
> reflection, I got all the currency managers tied to the same data source,
> then unbound all controls bound to those currency managers, navigated the
> currency managers, then rebound the controls. The problem of course, is
> that
> the controls were still receiving event notifications and there was no way
> that I could find to unsubscribe and resubscribe them.
>
> Fortunately, the current method is far cleaner and much faster.
>
> Thanks for the help Nicholas.
>
> Pete
>
>[/color]

[Pete Davis]

Re: Calling an internal constructor

Oh well, I'm an idiot. I didn't have to jump through all those hoops with
reflection. I could have simply created a new BindingContext object
unrelated to the form and gotten my CurrencyManager s from that. Live and
learn....

Pete


"Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard .caspershouse.c om> wrote in
message news:uWJfxO6OFH A.2468@tk2msftn gp13.phx.gbl...[color=blue]
> Pete,
>
> I don't think I really did much here, but you are welcome!
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - mvp@spam.guard. caspershouse.co m
>
> "Pete Davis" <pdavis68@NOSPA M.hotmail.com> wrote in message
> news:uJ-dnU4s148J6MjfRV n-jg@giganews.com ...[color=green]
> > It took a little trickery, but I managed to also create the
> > RelatedCurrency Manager.
> >
> > This is fantastic since this really solves my major problem.
> >
> > My problem is that I have a custom hierarchical grid control and unlike
> > the
> > MS DataGrid, this one is really hierarchical in the sense that you can
> > have
> > multiple parents expanded or collapsed at a given point.
> >
> > My problem was I needed to traverse the data hierarchy to figure out the
> > parents and children in the hierarchy. I could have written code to
> > duplicate what the CurrencyManager does, I suppose, but why re-invent[/color][/color]
the[color=blue][color=green]
> > wheel? So instead, I create these "shadow" currency managers that aren't
> > in
> > BindingContext and thus not bound to any controls, but still allow me to
> > navigate the records without affecting other controls that are bound to
> > the
> > same data source.
> >
> > This has been plagueing me for weeks. I kept coming up with different
> > ideas
> > but nothing was working. My last attempt was pretty extreme. Using
> > reflection, I got all the currency managers tied to the same data[/color][/color]
source,[color=blue][color=green]
> > then unbound all controls bound to those currency managers, navigated[/color][/color]
the[color=blue][color=green]
> > currency managers, then rebound the controls. The problem of course, is
> > that
> > the controls were still receiving event notifications and there was no[/color][/color]
way[color=blue][color=green]
> > that I could find to unsubscribe and resubscribe them.
> >
> > Fortunately, the current method is far cleaner and much faster.
> >
> > Thanks for the help Nicholas.
> >
> > Pete
> >
> >[/color]
>
>[/color]