Thread: list box in mfc, get data from file

Well here is the example that you asked for:

First create a drop box.
Use class wizard to give the drop box a member variable m_drItems.

Now in your dialog look for CDialog::OnInitDialog(); and place this code there.

Code:

	///////////Code starts here/////////////
        char x[1000000];  //make big enough to cover file
        CString buffer;
	ifstream file;

	//Open file
	file.open("items.txt", ios::in);  //What ever your file is

	//Check for file exist
	if(!file)
	{
		CString facts = "File not found";
		MessageBox(facts,NULL,MB_OK);
	}

	//Read data
	while(!file.eof())
	{
		char x;
		file.get(x);
		if(x=='\n')
		{
		
		m_drItems.AddString(buffer);
		//MessageBox(buffer,NULL,MB_OK); //Test buffer
		buffer="";
		}
		else
			buffer = buffer + x;
	}
	//MessageBox(buffer,NULL,MB_OK); //Test buffer
	m_drItems.AddString(buffer);
	m_drItems.SetWindowText(buffer);

	UpdateData(FALSE);

The problem is with the last entry. It has a strange effect.
You might have to check for spaces in the file. I didn't include this because of the file I use has no spaces.
Also you have to #include <fstream.h> at the top under all the other #include's.

P.S. If anyone know how to fix the last entry so that it is correct, that would be nice. Thanks

P.S. If anyone know how to fix the last entry so that it is correct, that would be nice.

I think it's probably due to the way you are reading the file (get() will read eof but the loop won't be terminated until the remainder of it's body has executed). Change -

while(!file.eof())

to -

while(file.get(x))

Change -

while(!file.eof())

to -

while(file.get(x))

I tried that, no errors, but it turns my input into garbage (jibberish).

The way that I ended up fixing it was to put a carage return at the end of the .txt file and taking this line of code out:

Code:

	//MessageBox(buffer,NULL,MB_OK); //Test buffer
	m_drItems.AddString(buffer);
	m_drItems.SetWindowText(buffer);

Then I moved these lines:

Code:

        char x[1000000];  //make big enough to cover file
        CString buffer;

To the top of the file under the line that says:

Code:

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

//Global variables///////////////
char x;                      ////  x for buffer to load from file
CString buffer;              ////  buffer for ifstream
/////////////////////////////////

Changed char x[1000000]; to char x;

>>C:\dave\mita\mitaDlg.cpp(112) : error C2660: 'eof' : function does not take 1 parameters

This is probly due to the fact of giving this line of code perameters: while(!file.eof()) you have to leave it empty. If you put: while(!file.eof(x)) this could be the problem.

>>C:\dave\mita\mitaDlg.cpp(119) : error C2039: 'AddString' : is not a member of 'CString'
>>c:\program files\microsoft visual studio\vc98\mfc\include\afx.h(368) : see declaration of 'CString'

If you did everythig explaned in the first code + the changes it shoud work. I know it compiles for me.

>>C:\dave\mita\mitaDlg.cpp(119) : error C2039: 'AddString' : is not a member of 'CString'
>>c:\program files\microsoft visual studio\vc98\mfc\include\afx.h(368) : see declaration of 'CString'

When you created the member variable, did you change the catagory to Control? If you didn't you have to change the catagory to Control from Value. Delete the variable that you created the first time and add another variable and make these changes.

Sorry about that, I forget what I do behind the code sometimes.

Try something like this -

Code:

ifstream file; 
char x;
CString buffer;
//Open file 

file.open("items.txt", ios::in); //What ever your file is 
 

//Check for file exist 
if(!file) 
{ 
	CString facts = "File not found"; 
	MessageBox(facts,NULL,MB_OK); 
} 

//Read data 
while(file.get(x)) 
{ 

	if(x=='\n') 
	{ 
		m_drItems.AddString(buffer); 
		//MessageBox(buffer,NULL,MB_OK); //Test buffer 
		buffer=""; 
	} 
	else 
	buffer = buffer + x; 
} 


	m_drItems.AddString(buffer); 
	UpdateData(FALSE);

assuming m_drItems is your list box control variable.

..although since you're using MFC you could use the CStdioFile class.

If it compiles ok, then it could be the location of your .txt file or the contents of the .txt file.

First the contents of the text file:
Spaces will cause problems with the control. It will cause empty entries or cause it to be completely empty.
If the contents have spaces then you have to check for spaces.

Code:

//Read data 
while(file.get(x)) 
{ 

	if(x=='\n') 
	{ 
		m_drItems.AddString(buffer); 
		//MessageBox(buffer,NULL,MB_OK); //Test buffer 
		buffer=""; //Make sure no spacer in between here. This will clear buffer and make it empty
	} 
        else if(x==' ') //Make sure you have a space in between the ' '
        {
                //This will add the item to the list
                m_drItems.AddString(buffer);
                buffer="";  //No space

                //To ignore the space, do nothing.  Leave this bracket empty, or comment out the code above.
        }
	else 
	buffer = buffer + x;

Second the location:
The code that checks file : if(!file) might not check for existance of file. Change it to if(file.fail()). I didn't test it, buy try that if you still have problems email me.