Managed C++/CLI

Put value on Form from FolderBrowserDialog

25-Feb-07 23:17

Vichitram wrote:

I am using VC++ 6.0

Then you're plainly not using C++/CLI

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Getting IP Address

Hamid_RT1-Mar-07 6:49

Hamid_RT

1-Mar-07 6:49

See http://visualcpp.org/template_permalink.asp?id=104[^]

WhiteSky

Girkers24-Feb-07 21:54

Girkers

24-Feb-07 21:54

I am trying to use a FolderBrowserDialog to get a folder and set the path to a text field on my form. The first problem I came up against was a blank folder listing which I had to rectify by making the FolderBrowserDialog spawn as a STA ApartmentState. Now the problem is that I can't get the SelectedPath back onto my calling form.

Here is my code for my Click event to open the FolderBrowserDialog and the subsequent settings:

private: System::Void OnClicked_ID_GETPHOTO_DIR(System::Object^  sender, System::EventArgs^  e) {<br />
			Thread^ newThread = gcnew Thread ( gcnew ThreadStart( this, &Picture_Importer::Form_Start::Get_Directory ) );<br />
			newThread->SetApartmentState(ApartmentState::STA);<br />
			newThread->Start();<br />
		}<br />
<br />
private: void Get_Directory() {<br />
		 	// Set defaults for Browsing<br />
			this->folderBrowserDialog1->SelectedPath = "c:\\";<br />
			     <br />
			// Set the help text description for the FolderBrowserDialog.<br />
			this->folderBrowserDialog1->Description = "Select the directory that you want to use as the default.";<br />
<br />
			// Do not allow the user to create new files via the FolderBrowserDialog.<br />
			this->folderBrowserDialog1->ShowNewFolderButton = false;<br />
			<br />
			// Show the FolderBrowserDialog.<br />
			System::Windows::Forms::DialogResult result = folderBrowserDialog1->ShowDialog();<br />
			if ( result == ::DialogResult::OK )<br />
			//if (folderBrowserDialog1->ShowDialog() == ::DialogResult::OK)<br />
				  {<br />
					 folderName = folderBrowserDialog1->SelectedPath;<br />
					 this->ID_PHOTO_DIR->Text = folderName;<br />
				  }<br />
		 <br />
		 }

The problem is when I run the code and it gets to this->ID_PHOTO_DIR->Text = folderName; it chokes with

An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll<br />
<br />
Additional information: Cross-thread operation not valid: Control 'ID_PHOTO_DIR' access from a thread other than the thread it was created on.

I am new to this programming language, so please be gentle with me. I appreciate what the message is saying I just don't get how to fix it.

Re: Put value on Form from FolderBrowserDialog

Girkers2-Mar-07 17:25

Girkers

2-Mar-07 17:25

I have found the answer on another forum with a very helpful person. The answer is here:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1297112&SiteID=1&mode=1

[C] Multithreading in windows

venetus24-Feb-07 16:05

24-Feb-07 16:05

Hi!!
I've been reading about multithreading in this page, but i can't compile the example written here.
I'm using Borland C++ 5.5.1 for Win32 and my config files are
bcc32

-I"C:\Borland\BCC55\Include"<br />
-L"C:\Borland\BCC55\Lib;C:\Borland\BCC55\Lib\PSDK<br />
-P<br />
-v-<br />
-w<br />
-D_WIN32_WINNT=0x0400

Ilink32

-v-<br />
-x<br />
-L"C:\Borland\BCC55\Lib;C:\Borland\BCC55\Lib\PSDK;C:\WINDOWS\system32"

And the error that the compiler gives me is

Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland<br />
thread.c:<br />
Error E2268 thread.c 30: Call to undefined function '_beginthread' in function main()<br />
Error E2268 thread.c 46: Call to undefined function '_endthread' in function ThreadProc(void *)<br />
*** 2 errors in Compile ***<br />

can someone help me??
what am i doing wrong??
i'am a beginner in multithreading...
greetings!!

Christian Graus24-Feb-07 16:25

24-Feb-07 16:25

venetus wrote:
I'm using Borland C++ 5.5.1

Then you can't possibly be using C++/CLI. You could try the visual C++ forum, but a Borland forum would be more sensible, if there is one.

Newbie0025-Feb-07 0:03

Newbie00

25-Feb-07 0:03

As I can see there is no problem with multithreading, but with the functions You've used. Compiler doesn't know these functions. Have you included <process.h> ??

venetus25-Feb-07 2:47

25-Feb-07 2:47

i just copy and pasted the example...
what do you think i have to include???

venetus25-Feb-07 2:54

25-Feb-07 2:54

i've just compile the example with Dev and it worked. But i don't know why it doesn't work with Borland compiler...
Any hint?

Newbie0025-Feb-07 3:41

Newbie00

25-Feb-07 3:41

Which example? There are 3 examples Blush | :O

venetus25-Feb-07 3:43

25-Feb-07 3:43

this one "Download demo project in C - 3 Kb"
bye

Newbie0025-Feb-07 3:50

Newbie00

25-Feb-07 3:50

I've tried it with Builder 6.0 and it's worked fine.
Probably you haven't checked the Multi Threaded check box in File\new\other...\console wizard dialog. Make sure it's checked.

Christian Graus25-Feb-07 9:11

25-Feb-07 9:11

this is STILL the wrong forum to be talking about this.

[API] Add a dll

abbd24-Feb-07 4:55

abbd

24-Feb-07 4:55

i would add a dll in my project but i don't know how i can introduce him, iam viewing a reference but i can't add him, i work with Visual Studio 2005 please help me.
Thank you very mutch.

Re: [API] Add a dll

Christian Graus24-Feb-07 16:26

Re: Copy constructor [modified]

24-Feb-07 16:26

What is the DLL written in ? You can add references to COM dlls and .NET dlls ( assuming your question is in the right forum and you are using C++/CLI ), I don't think you can import plain dlls, you can p/invoke them ( again, if you really are using C++/CLI ).

Copy constructor

Karismatic23-Feb-07 17:09

Karismatic

23-Feb-07 17:09

hey guys,

few days ago somebody ask me that where it is mandatory to define copy constructor i.e without making an explicit call we can not solve our problem..

so i need to know what would be that condition as i am also searching for the same from 2-3 days ...

if anybody can help me in getting the answer i'll greateful to him/her..

Thank you

Regards,
Pankaj Sachdeva

Re: Copy constructor

prasad_som24-Feb-07 5:25

prasad_som

24-Feb-07 5:25

pan_angel wrote:
where it is mandatory to define copy construc

It is not mandateroy to define copy c'to. But, it is required to define in cases where, one of member variable is pointer and uses dynamic memory allocation.

class A
{
char *m_pName;
int m_nid;
public:
A(char *pName,int nId)
{
   m_pName = new char [strlen(pName)+1]  ;
   strcpy(m_pName,pName);
   nid = nId;
}
~A()
{
delete []m_pName;
m_pName = NULL;
}
};
int main()
{
  A aObj("Prasad",1);
  A aObj1 = aObj;//this will work, but its not safe as m_pName  of aObj1 become unusable once aObj is destroyed , 
//default copy s'tor does shallow copy
}

So should modify your defintion to,

class A
{
char *m_pName;
int m_nid;
public:
A(char *pName,int nId)
{
   m_pName = new char [strlen(pName)+1]  ;
   strcpy(m_pName,pName);
   m_nid = nId;
}
A(A& aObj)
{
   int  nMemoryToAlloacate = strlen(aObj's char pointer);
   m_pName = new char [nMemoryToAlloacate + 1]  ;
   strcpy(m_pName,aObj's char pointer);
   m_nid = aObj's m_nid ;
}

~A()
{
delete []m_pName;
m_pName = NULL;
}
};

Prasad
Notifier using ATL | Operator new[],delete[][^]

Paresh Chitte26-Feb-07 17:28

Paresh Chitte

26-Feb-07 17:28

Objects can be passed to functions by value or by reference. If they are passed by value, a copy of each object is passed to the function. The default method for creating the copy is memberwise copy (shallow copy). This can be modified by supplying a user-defined copy constructor.

Re: Copy constructor

Christian Graus24-Feb-07 16:27