Global string or modify string in function

[Jose Cintron]

Hello all. Newbie question here...

I have a program that needs to do 1 of 2 things
1. declare a global System::String (which I think can't be done, because
VS 2005 complains)
2. modify the System::String in one function

An example may be easier to understand... The question is how would I get
the second option to work???

--- First option
// All of my defines go here
#define fnOfFile "test.xml"
#define ErrorFNF 1
#define OK 0

// Global Vars
System::String GlobalString;

namespace ReportGenerator {

public ref class Form1 : public System::Windows ::Forms::Form
{

private: int CheckFiles()
{
// If file is in current directory
GlobalString = String::Concat( ".\\" + fnOfFile);
// else If file is in parent directory
GlobalString = String::Concat( "..\\" + fnOfFile);
// else
return ErrorFNF;

return OK;
}

private: System::Void btnGenerate_Cli ck(System::Obje ct^ sender,
System::EventAr gs^ e)
{
// some code here
status = CheckFiles();
}
}
}


--- Second option
// All of my defines go here
#define fnOfFile "test.xml"
#define ErrorFNF 1
#define OK 0

namespace ReportGenerator {

public ref class Form1 : public System::Windows ::Forms::Form
{

private: int CheckFiles(Syst em::String^ aString)
{
// If file is in current directory
aString = String::Concat( ".\\" + fnOfFile);
// else If file is in parent directory
aString = String::Concat( "..\\" + fnOfFile);
// else
return ErrorFNF;

return OK;
}

private: System::Void btnGenerate_Cli ck(System::Obje ct^ sender,
System::EventAr gs^ e)
{
System::String FileName = "";
// some code here
status = CheckFiles(File Name);
// Now FileName has the correct location (if the file was found)
}
}
}

[Bruno van Dooren [MVP VC++]]

Re: Global string or modify string in function

Hello all. Newbie question here...

>
I have a program that needs to do 1 of 2 things
1. declare a global System::String (which I think can't be done,
because VS 2005 complains)
2. modify the System::String in one function

Something like this would work, if you need a global:
ref class myGlobal
{
public:
static String ^globalString;
static myGlobal()
{
globalString = nullptr;
}

};

you cannot create globals, but it is perfectly valid to create a class,
solely for the purpose of containing public static (i.e. global) variables.
myGlobal::globa lString = "Hello";
The static constructor ensures that the global has a know value at startup.

Alternatively, if you want to change a string that you pass to a function,
you have to pass it by reference (%).
If you didn't use %, the caller would still point to the same string.
You do that like this:

reg class Test
{
// ..
static void ChangeString(St ring ^ %str)
{
str = "Test";
}
};

--

Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"

[Jose Cintron]

Re: Global string or modify string in function

Thanks Bruno

I also though about crating a class to hold all of the global crap. I guess
I can do that fro version 2.0 for the moment I got it to work by doing
something like...

private: int CheckFiles(Syst em::String^ &aString)
{
// If file is in current directory
aString = ".\\" + fnOfFile;
// else If file is in parent directory
aString = "..\\" + fnOfFile;
// else
return ErrorFNF;

return OK;
}

private: System::Void btnGenerate_Cli ck(System::Obje ct^ sender,
System::EventAr gs^ e)
{
System::String FileName = "";
// some code here
status = CheckFiles(File Name);
// Now FileName has the correct location (if the file was found)

"Bruno van Dooren [MVP VC++]" <bruno_nos_pam_ van_dooren@hotm ail.comwrote
in message news:edV9cAS0GH A.328@TK2MSFTNG P06.phx.gbl...

>Hello all. Newbie question here...
>>
>I have a program that needs to do 1 of 2 things
> 1. declare a global System::String (which I think can't be done,
>because VS 2005 complains)
> 2. modify the System::String in one function

>
Something like this would work, if you need a global:
ref class myGlobal
{
public:
static String ^globalString;
static myGlobal()
{
globalString = nullptr;
}
>
};
>
you cannot create globals, but it is perfectly valid to create a class,
solely for the purpose of containing public static (i.e. global)
variables. myGlobal::globa lString = "Hello";
The static constructor ensures that the global has a know value at
startup.
>
Alternatively, if you want to change a string that you pass to a function,
you have to pass it by reference (%).
If you didn't use %, the caller would still point to the same string.
You do that like this:
>
reg class Test
{
// ..
static void ChangeString(St ring ^ %str)
{
str = "Test";
}
};
>
--
>
Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"
>

[Jose Cintron]

Re: Global string or modify string in function

I'm trying to get the class idea to work since it seems that I'm going to
need to save the default path from where the program was started, and some
other seetings, but I'm running into some problems

here's what I have

#pragma once

// bunch of defines

ref class GlobalSettings
{
public:
static String^ appPath;

static GlobalSettings( )
{
appPath = System::IO::Dir ectory::GetCurr entDirectory();
}
}

namespace ReportGenerator {

private: System::Void btnGenerateRepo rt_Click(System ::Object^ sender,
System::EventAr gs^ e)
{
// initialize some stuff...

MessageBox::Sho w(GlobalSetting s::appPath, "", MessageBoxButto ns::OK,
MessageBoxIcon: :Error);
}
}

When I compile I get
error C2143: syntax error : missing ';' before '^'
error C4430: missing type specifier - int assumed. Note: C++ does not
support default-int


"Bruno van Dooren [MVP VC++]" <bruno_nos_pam_ van_dooren@hotm ail.comwrote
in message news:edV9cAS0GH A.328@TK2MSFTNG P06.phx.gbl...

>Hello all. Newbie question here...
>>
>I have a program that needs to do 1 of 2 things
> 1. declare a global System::String (which I think can't be done,
>because VS 2005 complains)
> 2. modify the System::String in one function

>
Something like this would work, if you need a global:
ref class myGlobal
{
public:
static String ^globalString;
static myGlobal()
{
globalString = nullptr;
}
>
};
>
you cannot create globals, but it is perfectly valid to create a class,
solely for the purpose of containing public static (i.e. global)
variables. myGlobal::globa lString = "Hello";
The static constructor ensures that the global has a know value at
startup.
>
Alternatively, if you want to change a string that you pass to a function,
you have to pass it by reference (%).
If you didn't use %, the caller would still point to the same string.
You do that like this:
>
reg class Test
{
// ..
static void ChangeString(St ring ^ %str)
{
str = "Test";
}
};
>
--
>
Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"
>

[Jose Cintron]

Re: Global string or modify string in function

Got passed that it was missing a ; at the end of the class definition. Now
my problem is that if I stick the definition before Form1's definition all
hell breaks loose and when I try to compile I get a message to the effect
that Form1 is not the first class. If I move the definition to after Form1
I get messages saying that it cannot find the definition for GlobalSettings

"Jose Cintron" <l0rddarkf0rce@ hotmail.comwrot e in message
news:%23q1hSsS0 GHA.4580@TK2MSF TNGP05.phx.gbl. ..

I'm trying to get the class idea to work since it seems that I'm going to
need to save the default path from where the program was started, and some
other seetings, but I'm running into some problems
>
here's what I have
>
#pragma once
>
// bunch of defines
>
ref class GlobalSettings
{
public:
static String^ appPath;
>
static GlobalSettings( )
{
appPath = System::IO::Dir ectory::GetCurr entDirectory();
}
}
>
namespace ReportGenerator {
>
private: System::Void btnGenerateRepo rt_Click(System ::Object^ sender,
System::EventAr gs^ e)
{
// initialize some stuff...
>
MessageBox::Sho w(GlobalSetting s::appPath, "", MessageBoxButto ns::OK,
MessageBoxIcon: :Error);
}
}
>
When I compile I get
error C2143: syntax error : missing ';' before '^'
error C4430: missing type specifier - int assumed. Note: C++ does not
support default-int
>
>
"Bruno van Dooren [MVP VC++]" <bruno_nos_pam_ van_dooren@hotm ail.comwrote
in message news:edV9cAS0GH A.328@TK2MSFTNG P06.phx.gbl...

>>Hello all. Newbie question here...
>>>
>>I have a program that needs to do 1 of 2 things
>> 1. declare a global System::String (which I think can't be done,
>>because VS 2005 complains)
>> 2. modify the System::String in one function

>>
>Something like this would work, if you need a global:
>ref class myGlobal
>{
>public:
> static String ^globalString;
> static myGlobal()
> {
> globalString = nullptr;
> }
>>
>};
>>
>you cannot create globals, but it is perfectly valid to create a class,
>solely for the purpose of containing public static (i.e. global)
>variables. myGlobal::globa lString = "Hello";
>The static constructor ensures that the global has a know value at
>startup.
>>
>Alternativel y, if you want to change a string that you pass to a
>function, you have to pass it by reference (%).
>If you didn't use %, the caller would still point to the same string.
>You do that like this:
>>
>reg class Test
>{
>// ..
> static void ChangeString(St ring ^ %str)
> {
> str = "Test";
> }
>};
>>
>--
>>
>Kind regards,
> Bruno van Dooren
> bruno_nos_pam_v an_dooren@hotma il.com
> Remove only "_nos_pam"
>>

>
>

[Bruno van Dooren [MVP VC++]]

Re: Global string or modify string in function

Got passed that it was missing a ; at the end of the class definition.

Now my problem is that if I stick the definition before Form1's definition
all hell breaks loose and when I try to compile I get a message to the
effect that Form1 is not the first class. If I move the definition to
after Form1 I get messages saying that it cannot find the definition for
GlobalSettings

Could you post the exact compiler error message, possibly with some of the
code that causes the error?
Otherwise I'll be forced to make jokes about my crystal ball, in a monty
python'esque way.
;-)

--

Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"

[Jose Cintron]

Re: Global string or modify string in function

I fugure the problem out... I just moved the definition of my global class
to inside the definition for the Form1 class and everything worked fine...
Go for it just <INSERT JOKE HEREI deserve it.

"Bruno van Dooren [MVP VC++]" <bruno_nos_pam_ van_dooren@hotm ail.comwrote
in message news:eG2WwKc0GH A.4748@TK2MSFTN GP04.phx.gbl...

>Got passed that it was missing a ; at the end of the class definition.
>Now my problem is that if I stick the definition before Form1's
>definition all hell breaks loose and when I try to compile I get a
>message to the effect that Form1 is not the first class. If I move the
>definition to after Form1 I get messages saying that it cannot find the
>definition for GlobalSettings

>
Could you post the exact compiler error message, possibly with some of the
code that causes the error?
Otherwise I'll be forced to make jokes about my crystal ball, in a monty
python'esque way.
;-)
>
--
>
Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"
>

[Bruno van Dooren [MVP VC++]]

Re: Global string or modify string in function

>I fugure the problem out... I just moved the definition of my global class

>to inside the definition for the Form1 class and everything worked fine...
>Go for it just <INSERT JOKE HEREI deserve it.

Hey,
We all have to start sometime.
When I was a C++ newbie, I also made a lot of basic mistakes. There's no
shame in making mistakes.
Besides, I already made my crystal ball joke.
;-)

--

Kind regards,
Bruno van Dooren
bruno_nos_pam_v an_dooren@hotma il.com
Remove only "_nos_pam"

[Ben Voigt]

Re: Global string or modify string in function

I know you already solved it, but here's another way:

>
// Global Vars
System::String GlobalString;

gcroot<System:: String^GlobalSt ring;