Passing Data Between Forms, I tried and failed :) - Managed C++/CLI Discussion Boards

Following is my issue.

-------------------------------------------

I have a unmanaged application ( C++ , .exe ) which has a class CMyClass
with a public member fMyFunct(). You can assume this C++ application is built with /clr option.

I need to instantiate CMyClass in a different managed ( C# ) application and call fMyFunct().

Many thanks if any of you can send me a sample which demonstrate above things ( Remember I can't manipulate C++ application apart from project settings. But you can do anything in C# application )

----------------------------------------------------

You can't create native/unmanaged C++ objects from managed code like C#.

You need to write a managed (ref) class wrapper for the unmanaged C++ class.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Hi, I m a VC++ guy, i have worked on VC++ / MFC / C++ . But at present working only on C++ . Like to move into .Net , can someone guide me which would be the better option to learn WebApplications Or windows application , even in case of Carrier growth.

Also VC++.NET has scope like C# ?

Newww

I'd say C# and Winforms first, then move into C#/ASP.NET. that means you'll be on more stable ground as you move into C#.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Hi Thanks , Can u guide me how to learn Windows forms (thou i m experianced in MFC) and web application faster ? Doing small applications or learning the concepts of .Net and etc ?

Thanks.

I am trying to cut 3 bytes from the data read from the file and keep getting error. Here is the error and the code.
**************************************************
///error C2228: left of '.substr' must have
class/struct/union
***************************************************

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <conio.h>
#include <string>
#include <fstream>

using namespace std;
string DataCut;

struct s {
char test[4];
char test1[4];
};
struct s myStr;

int _tmain(int argc, _TCHAR* argv[])
{

char *str1, Mycut[4];
char str[80000];

string sear1;
size_t result;

fstream file_op("c:\\ProjectRead.txt",ios::in);
while(!file_op.eof())
{
file_op.getline(str, 80000);
str1 = str;
*********************************************************************
Mycut = str.substr(0,4); /// Error here
cout << str1;
*********************************************************************

} file_op.close();

system("PAUSE");
return 0;
}

Since this question is unrelated to managed C++, please post on the correct
board - The Visual C++ / MFC Board[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Hi, I tried to pass data between forms in VC++. I want to pass input data from child's textboxes to parent when child form closes.
But all i have is errors. Can you tell me where my mistake(s) is ?

//R2.h (Parent Form)

#include Yeni.h
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;

namespace xxx {
public ref class R2 : public System::Windows::Forms::Form
{
........... auto generated code.............
}

//The Button which creates Child Form
private: System::Void pictureBox2_Click(System::Object^ sender, System::EventArgs^ e) {
MdiParent->ActiveMdiChild->Close();
Yeni^ YRForm = gcnew Yeni();
YRForm->MdiParent=this->MdiParent;
YRForm->Show();}

//The Button in child form, which closes child form
private: System::Void Yeni::pictureBox1_Click(System::Object^ sender, YeniUpdateEventArgs^ e)
{
String^ A = e->Isim;
String^ B = e->Soyad;
MessageBox::Show(this,"Isim : "+A+"Soyad : "+B,"Durum",MessageBoxButtons::OK);
}

//Yeni.h (Child Form) (I'm not sure where I should add "delegate")

using namespace System;
using ..........
....

namespace xxx {

public: delegate void YeniUpdateHandler(System::Object^ sender, YeniUpdateEventArgs^ e);
public: YeniUpdateHandler^ YeniUpdated;

public ref class YeniUpdateEventArgs : public System::EventArgs
{

private: String^ mIsim;
private: String^ mSoyad;

public: YeniUpdateEventArgs(String^ sIsim, String^ sSoyad)
{
this->mIsim = sIsim;
this->mSoyad = sSoyad;
}
public:
property String^ Isim
{
String^ get
{
return mIsim;
}
}
public:
property String^ Soyad
{
String^ get
{
return mSoyad;
}
}
};

public ref class Yeni : public System::Windows::Forms::Form
{
........... auto generated code.............
}

//The Button which closes child form
private: System::Void pictureBox1_Click(System::Object^ sender, System::EventArgs^ e) {
String^ sIsim = textBox1->Text;
String^ sSoyad = textBox2->Text;
YeniUpdateEventArgs^ args = gcnew YeniUpdateEventArgs(sIsim, sSoyad);
YeniUpdated(this, args);
this->Close();

}

I have 84 errors Smile | :)

) Most of them is syntax errors. What are my mistakes ? Is anything missing in code or did i place smtg wrong?
Thank you very much...

PS:Please don't suggest any solution or example in VC#, because after i tried to translate, onlything that i had was errors and i
didn't have find any example in VC++.

What are the 84 errors you are getting?

"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon

Thank your for your respond. Finally i solved it. I add a new header to project and move the EventArgs class to there. Now it works...

Hi, I'm using C++/CLI with Visual Studio 2005. I have finally gotten my ListView control to function properly when I add records to the control because there is a this->myListView->Items->Add(record). But the this->myListView->Items::get() function returns a ListViewItemCollection^ but the code will not let me define a ListViewItemCollection^ to read the collection into. I have been Googling this all day it's gotten to be hair pulling time. I have a ListView with 4 columns and all I want to do is walk the list, read each record, and sperate the record's fields into the appropriate variables. Any help would be appreciated.

Thanks,
Buck

I don't think you can create one, it needs to be attached to a listview. Read the items directly, or create a typed List to copy them into with foreach, if you must.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Yes, reading the items directly would be fine. How do you do that? I can define the record and while trapped in the debugger I can see the information but it is of type ListViewSubItemCollection^ and the compiler will not let me define one. Here is the code.

ListViewItem^ myRecord = gcnew ListViewItem();
myRecord = this->myListView->Items[0];
ListViewSubItemCollection^ myCollection = myRecord->SubItems::get(); // It won't let me define this collection.

If I trap after assigning Items[0] to myRecord I can go to either the Autos or Locals tab and expand myRecord and I can see subItems collection with the data or expand the SubItems and I can see the subItems collection. I just need the correct syntax to read the data from the ListView.

Buck

Get is a "getter" method for a property. You don't call it directly.

Does this work?

ListViewSubItemCollection^ myCollection = myRecord->SubItems;

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Hi Mark,

No, if I try to define like that the compiler complains that ListViewSubItemCollection^ is not defined (the namespace System::Collections is defined). I get the same error if I try to define a ListViewItemCollection^ or if I try to use gcnew with them.

Yeah, I usually don't call ::get(). I will type it out that way so that I can see through the intellisense what type the get() function is going to return and then I can define an appropriate variable.

If you ever find out of a way to declare a ListViewItemCollection^ or ListViewSubItemCollection^ email me if you can.

Thanks,
Buck

See my code in my most recent post - I tested it, it works fine.

The compiler will always complain if it doesn't know the type.

The "ListViewItem::ListViewSubItemCollection" class is not in "System::Collections".
It's in System::Windows::Forms.

"ListViewSubItemCollection" is a ~~subclass~~ nested class in the "ListViewItem" class.

The fully qualified type is "System::Windows::Forms::ListViewItem::ListViewSubItemCollection"

Of course, if you have "using System::Windows::Forms;" somewhere above, you can shorten the type to
"ListViewItem::ListViewSubItemCollection".

Make sense?

Mark

Last modified: 22mins after originally posted --

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Yeah it makes sense, but I didn't know that ListViewItemCollection was of type ListViewItem. Just not intuitively obvious when writing code.

Buck

I've got it now.

String^ field_1;
String^ field_2;
String^ field_3;

for each(ListViewItem^ record in myListView->Items)
{
field_1 = record->SubItem[0]->Text;
field_2 = record->SubItem[1]->Text;
field_3 = record->SubItem[2]->Text;
}

I had to figure this one out on my own. Any example I found on the web did not work for me. I'm amazed that reading from a ListView was not covered in Stephen Frasers book on C++/CLI which is very in depth.

I could not find any example of this in the Microsoft documentation either. I guess we're supposed to know this though some kind of mental osmossis.

Thanks,
Buck

That's fine. You can also do this, like you were trying to do before...

ListViewItem^ myRecord = this->listView1->Items[0];
System::Windows::Forms::ListViewItem::ListViewSubItemCollection^myCollection = myRecord->SubItems;

String ^field_1 = myCollection[0]->Text;
String ^field_2 = myCollection[1]->Text;
String ^field_3 = myCollection[2]->Text;

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Thanks Mark,

I hate those kind of full namespace declarations. I really don't understand why sometimes you have to include the entire namespace name even though the namespace has already been defined with the 'using' keyword. It wouldn't be so bad if there was a list of types that require the full "path" for lack of a better word.

Buck

BuckBrown wrote:
I really don't understand why sometimes you have to include the entire namespace

You don't, if you use "using"...

using namespace System::Windows::Forms;
...
ListViewItem^ myRecord = this->listView1->Items[0];
ListViewItem::ListViewSubItemCollection^myCollection = myRecord->SubItems;
String ^field_1 = myCollection[0]->Text;
...

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

This is a good example of how to determine if I need to include the preceding ListViewItem:: (or any other preceding datatype: Smile | :)

. I have run into declaration problems like this before but those first two lines after the ellipsis are illustrative of the approach. I am printing that one for my notes.

Buck

I didn't state that correctly, and I modified my post above...

ListViewSubItemCollection is a ~~subclass~~ nested class in the ListViewItem class.

It's the same thing you'd have to do with regular C++... the compiler has to
know the class and the namespace Smile | :)

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Hi, I'm using C++/CLI and Visual Studio 2005. I have a list view control that I would like to have the columns center justified. I can center justify all the columns except the first column. The GUI designer will not change from left to center justified and if I hard code the justification it still will not do it. Is this a subtle bug? Why won't the first column center justify?

Thanks
Buck

Hi to everybody..
i want to this book ...is there any url is there for downloading this book .plz ...
The MFC Answer Book: Solutions for Effective Visual C++ Applications by Eugene Kain

*****THANKS N ADVANCE****
Mathen.K
(I WILL TRY MY LEVEL BEST )