String::Format problem

[Derek =?utf-8?Q?Kuli=C5=84ski?= / takeda]

I spent many hours on this, googling around and experimenting, and still
nothing.

I wrote an umanaged program (actually various classes), while I was
developing them I used command line to test it.
Now, I decided to make GUI for it, so I created new project: "Windows Forms
Application (.NET)" (I was trying to use something that's not managed (e.g.
MFC, but I learned quickly that I don't actually know how to use MFC :)
In .NET I was able to quickly create the GUI that looked as I wanted it too
look.

Now my problem is really silly. While I figured out how to convert
System::String to for example std::string, and looks like the other way
around is actually easy, I can't for a love of God make String::Format do
what I want.
Even the examples from MSDN doesn't work when I copy&paste them verbatim!
Here is an example:
http://msdn2.microsoft.com/en-us/library/fht0f5be.aspx

In a simple program that has just textbox, button and label, the following
code works:
label1->Text = String::Format( "Hello, {0}", textBox1->Text);

But this, doesn't want to:
label1->Text = String::Format( "Hello, {0}", 10);

My goal is basically do something like this:
unsigned short int pc = 8000;
label1->Text = String::Format( "Address: {0,4:X}", pc);

Anyone has idea what I'm doing wrong?

I have also an unrelated question: If I have a managed class (for the
form), and I define inside a pointer to an unmanaged class, is that a good
practice? Right now it appears to work fine, but before I had an exception
that the pointer is null (even though I did new on the form's load, and
pointer was used after selecting an option from a menu). I have no idea how
I even fixed it.

Thanks for help.
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[Ben Voigt [C++ MVP]]

Re: String::Format problem

My goal is basically do something like this:
unsigned short int pc = 8000;
label1->Text = String::Format( "Address: {0,4:X}", pc);

Would this be sufficient for you?
label1->Text = "Address: " + pc.ToString("X4 ");

>
Anyone has idea what I'm doing wrong?
>
I have also an unrelated question: If I have a managed class (for the
form), and I define inside a pointer to an unmanaged class, is that a good
practice? Right now it appears to work fine, but before I had an exception
that the pointer is null (even though I did new on the form's load, and
pointer was used after selecting an option from a menu). I have no idea
how
I even fixed it.

That is the right way to use native classes from managed code. Often, you
create a managed class to wrap each native object, and its only
responsibility is taking care of that one native pointer.

>
Thanks for help.
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????

[Ben Voigt [C++ MVP]]

Re: String::Format problem


[snip]

Maybe there's some option enabled in my VC++ (it is from VS 2003), but
which option is responsible for that?

[snip]

I'm really wondering what's wrong with my C++ compiler. Even examples on
MSDN webpage didn't work.

You need an upgrade to VC 2005, even Express Edition will work. Managed
Extensions for C++ that came with VC 2003 were so full of problems that
Microsoft started over in VC 2005, giving us the C++/CLI language.

[Derek =?utf-8?Q?Kuli=C5=84ski?= / takeda]

Re: String::Format problem

On Tue, 4 Sep 2007 11:13:07 -0500, Ben Voigt [C++ MVP] wrote:

You need an upgrade to VC 2005, even Express Edition will work. Managed
Extensions for C++ that came with VC 2003 were so full of problems that
Microsoft started over in VC 2005, giving us the C++/CLI language.

Actually one of the readers here (I don't know if he wants me to mention
his name since he answered privately) pointed me to use a __box() around
basic types like integers etc. which seems to do the thing. I can put char*
in String() and it seems to solve most of the problems.
He also recommended me to switch to VS 2005, and I'll try it as soon as I
can.

Anyway, thank you Ben for troubleshooting the problem, I really appreciate
that you tried to help.
I have another question about creating virtual listbox, but I'll create
another thread for it, since it is unrelated.

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