Managed C++/CLI

Passing data between forms

2-Jun-05 12:18

No worries - glad to help.

Christian Graus - Microsoft MVP - C++

richiemac1-Jun-05 8:58

1-Jun-05 8:58

I have two forms (Form1 and Form2). Form1 will create an instance of Form2. After some processing certain elements from Form2 will be passed back to Form1. I think I know what I need todo (roughly) but I have a problem including each Form header in the other. I don't think this is possible (is it?) so how do I go about creating instances of each form if I can't include their headers?

I know there was a similar post on this but it didn't answer my specific question.

Thanks in advance.

Saksida Bojan1-Jun-05 19:40

1-Jun-05 19:40

If you are including the same header to the forms, instead using #pragma once
use Old Defenition style Example:

#ifndef _CORE_H_
#define _CORE_H_

public __gc class Core
{
//To Do:
};

#endif //_CORE_H_

With this you can use it from anywhere and you can include header into any file. Or multiple file. you will not get redefenition error

Lagwagon561-Jun-05 10:12

Lagwagon56

1-Jun-05 10:12

I had a similar problem. I just created a class that I pointed both forms to and used it to pass information between the forms.
So creat a new __gc class. From form1 create an object of that class. then point it to form2's object.
Pass is the class i'm using to pass information.

<br />
//Form1.h<br />
Pass *pass = new Pass();<br />
Form2 *input = new Form2(); <br />
input->pass1 = pass;<br />
input->ShowDialog();<br />
<br />
label_InputSomthing->Text = pass->somthing;<br />
Invalidate();<br />
<br />
//Form2.h<br />
Pass *pass1;<br />
pass1->something = textBox_something->Text;<br />
<br />
Close();<br />

richiemac1-Jun-05 21:32

1-Jun-05 21:32

Thaks guys I'll give it a go.

Saksida - will the old style definitions go inside the namespace tag or outside. e.g

#ifndef _CORE_H_
#define _CORE_H_
namespace test
{ ... }
#endif

or

namespace test
{
#ifndef _CORE_H_
#define _CORE_H_
...
#endif
}

richiemac1-Jun-05 22:37

1-Jun-05 22:37

Do I need to use the #indef definition in both forms or jsut the main one?? If I use it in both I get errors.

error C2143: syntax error : missing ';' before '*'
error C2501: 'test::Form1::form2' : missing storage-class or type specifiers
error C2501: 'test::Form1::f2' : missing storage-class or type specifiers

When I try to declare an instance of form2.

If I use it in the main form only I get only one error.

error C2011: 'test::form2' : 'class' type redefinition

I could do with some help here. I'm not very experienced with c++ let alone managed c++. Been on this for a couple of days and nothing I try wants to work.

Lagwagon562-Jun-05 4:27

Lagwagon56

2-Jun-05 4:27

Make sure to #include both your passing class and form2 in your form1.

Saksida Bojan2-Jun-05 20:10

2-Jun-05 20:10

Yes you need to use but not #indef but #ifndef

And of course you need outside namespace. This means it must be in the beginning of file #ifndef and #define

And on the end it must be #endif

If you realy want to have an example then download this:
http://users.volja.net/bsaksida/CDDVD Organizer.zip[^]

Look under Core Folder, you will see CDDVDcore.h and you will see how has been defined. this program verzion is 0.1 there are a lot of bugs. Don't wory this program will be released as opensource.

richiemac5-Jun-05 5:34

5-Jun-05 5:34

Thanks for the help guys. I've written a little test prog that I've managed to get going with your help.

Thanks again. Smile | :)

panel component problems

richiemac31-May-05 6:44

31-May-05 6:44

Hi all,

I'm trying to create a few panels in a VC++.net application. I need the panels to be visible on a number of screens and I don't want to reproduce the same components many times over. When I run my app the panel is only visible in one screen only no matter what I do.

I'm doing something along the lines of

<br />
private: System::Void application_menuItem_Click(System::Object *  sender, System::EventArgs *  e)<br />
		 {<br />
			 this->application_panel->Visible = true;<br />
			 this->low_level_panel->Visible = false;<br />
		 }<br />

which works for one screen but not if I select any other screen.

Any ideas gratefully recieved.

Christian Graus31-May-05 13:49

31-May-05 13:49

What do you mean by a screen ? A form ? How does this panel get to be on these forms ?

Christian Graus - Microsoft MVP - C++

richiemac31-May-05 21:47

31-May-05 21:47

Sorry for the poor explanation.

I have a form (Form1), that has two panels on (panel1, panel2). This is where I'm becoming stuck. Each panel is supposed to show a number of components with some of these components being on both. I've grouped these components together and added them to another panel (panel3). Form1 has a menu item which is used to choose panel1 or 2.

So I have something like

<br />
private: System::Void menuItem1_Click(System::Object * sender, System::EventArgs * e)<br />
{<br />
this->panel1->Visible = true;<br />
this->panel2->Visible = false;<br />
}<br />

to show the appropriate panel. Now what I also need to do is add panel3 to the visible panel. So I'm doing - or trying to do - something like

<br />
if ( this->panel1->Visible == true )<br />
{<br />
this->Controls->Add( this->panel3 );<br />
}<br />

But I can only get panel3 to show itself on one panel. Either panel1 or panel2 but never both.

Christian Graus31-May-05 21:51

31-May-05 21:51

I'd have thought the trick would be to move panel3 to be top in the z-order, so it is always visible above panel 1 OR 2, without adding it to either, just because it's part of the form.

Otherwise, do they have to be the same instance ? Perhaps you could create a control, add it to both panels, and then pass the data between the two so they look the same in terms of what is set on them ? Or do it using events ?

Christian Graus - Microsoft MVP - C++

richiemac31-May-05 22:43

31-May-05 22:43

So basically have panel3 floating over the other panels. How do you change the z-order (sorry but new to all this)? And will this then lock the panel to its correct location throughout the forms lifespan?

Christian Graus1-Jun-05 11:11

1-Jun-05 11:11

In managed C++ - use SetWindowPos to set the Z order to top. The panel shouldn't move, unless you tell it to.

Christian Graus - Microsoft MVP - C++

Christian Graus1-Jun-05 11:12

1-Jun-05 11:12

In MC++, use SetWindowPos with SWP_NOMOVE | SWP_NOSIZE and a position of TOP.

Christian Graus - Microsoft MVP - C++

richiemac6-Jun-05 0:16

6-Jun-05 0:16

Thanks for the help Christian.

Re: OleDB Question

Saksida Bojan1-Jun-05 19:34

Re: OpenFileDialog Problems

1-Jun-05 19:34

Also i have noticed that if i change select statment, there would not be any effect.

online users

K.A.L28-May-05 3:01

K.A.L

28-May-05 3:01

I would like to make a programme that list active users that are connected to my pc.
How do i get access to these information.
What should i look into?

OpenFileDialog Problems

vajjalu27-May-05 9:54

vajjalu

27-May-05 9:54

I have a button in a dialog which when clicked opens an OpenFileDialog box and the user can select a file. The problem I am facing is that when I try and copy the file & path using the FileName function into a CString, I keep getting a NULL value.

The thing is, the code works as intended in the debug mode but doesnt in the release mode.

Below is the code I am using:

void CDisColEnvDlg::OnBnClickedButtonLocalBrowse()
{
// TODO: Add your control notification handler code here
System::Windows::Forms::OpenFileDialog* appOpenFileDialog = new System::Windows::Forms::OpenFileDialog();
appOpenFileDialog->Filter = S"Trace File (*.tf1)|*.tf1";

if (appOpenFileDialog->ShowDialog() == System::Windows::Forms::DialogResult::OK)
{
CString szFileName = appOpenFileDialog->FileName;
AfxMessageBox(szFileName,MB_OK|MB_ICONINFORMATION,0);
}
}

Can anyone tell me what the problem potentially could be.

Also, is there a way to do this using unmanaged code?

Thanks in advance.

--
If a program is useless, it must be documented.

Christian Graus28-May-05 12:02

Re: OpenFileDialog Problems

28-May-05 12:02

vajjalu wrote:
Can anyone tell me what the problem potentially could be.

The string in the dialog is probably wide, try using _bstr_t.

vajjalu wrote:
Also, is there a way to do this using unmanaged code?

Yes, these dialogs exist in MFC, CFileDialog or COpenFileDialog or something. You can get at them without MFC as well, by filling a struct and passing it to an API function, I believe.

Christian Graus - Microsoft MVP - C++

Saksida Bojan29-May-05 4:56