Thread: File into Listbox

Hey,

I have a text file like this:

Code:

566.33
988.33
122.33
112.33
333.33

I need to put this file line by line into a ListBox control.

I know how to add the string to the listbox, if someone could just
give me some code to put in a loop that will read the file line by line into a string that i can then send to the listbox.

Thanks for any help.
TNT

Code:

#include <string>
using std::string;
#include <cstring>
#include <cstdlib>
#include <windows.h>

#define MAX_TOKENS 5

int main()
{
HANDLE hFile;
DWORD dwSize,dwReadSize;
char *lpBuffer = 0,
 *strPtr, //A pointer which is the return of strtok()
 *strP1[MAX_TOKENS];//Buffers as array of 2 pointers
int x = 0;
string sResult;

hFile = CreateFile("text.txt",GENERIC_READ,0, NULL,OPEN_EXISTING,
 FILE_ATTRIBUTE_NORMAL,
 NULL); //Open File for reading

if(!hFile){
MessageBox(0,"Error with file","Error",MB_OK);
exit(0);
}

dwSize = GetFileSize(hFile,NULL);//Get the size of the file
lpBuffer = (char*)GlobalAlloc(0,dwSize+1); //Create a read in buffer

if(!lpBuffer){
MessageBox(0,"Error with memory allocation","Error",MB_OK);
                CloseHandle(hFile);
exit(0);
}

ReadFile(hFile,lpBuffer,dwSize + 1,&dwReadSize,NULL);//Suck up file contents to buffer

lpBuffer[(int)dwSize] = '\0';//NULL terminate

char strcopy[(int)dwSize +1];//A copy to stop original info being chewed up

strcpy(strcopy,lpBuffer); //make copy to tokenize

strPtr = strtok(strcopy,"\n");//Set Strtok to beginning of strcopy. Use '\n' for delimiter

while(strPtr && x < MAX_TOKENS){//while token is not NULL and less than total tokens
strP1[x] = new char[100]; //Create space dynamically
strcpy(strP1[x],strPtr);//Copy token into buffer array
strPtr = strtok(NULL,"\n");//Force strtok up the string
x++;
}
for(int y = 0;y<x;y++){
sResult += "Found token - ";
sResult += strP1[y];
sResult += "\n";
delete strP1[y]; //Clean up after myself

//SetDlgText().......
}
MessageBox(0,sResult.c_str(),"Results",MB_OK);
GlobalFree(lpBuffer);//free memory
CloseHandle(hFile);//close file
return 0;
}

This fits in with what you were asking a while ago on strtok().

I reused the code I gave ,but read from a file and used '\n' as the token delimiter instead of space....

The code sucks up the contents of a file called "text.txt", makes a copy and then tokenises it.

I used some windows funcs CreateFile() & GlobalAlloc() cuz I am trying to get used to using them . Also I used the string class cuz its so easy to use.

Thanks Fordy thats what i wanted thers one problem though, i dont know how many tokens it will need to be in. This is because the program adds data to the file. So there wont be a set amount of lines to add to the list box. This means i cant define max tokens as 5, i was just using 5 as an example. Do you know how i can find out how many lines are in the file to start with.

Thanks alot
TNT

Yeah....

The way I would do it is with a variable sized container of some sort....

When I get home I'll work something out for you....

Do all lines in the file have the same length, (i.e. 6 characters)? If so you can divide the file size by the line length, (remembering the extra characters terminating the lines - load the file into a hex aditor), to find out how many lines.

Easier I would have thought, is to read the file one line at a time until you reach EOF.

Oooh, concurrence... we can't go on meeting like this Fordy!

#include <stdio.h>

Code:

  FILE *TextFile;
  char sFileName[] = "file1.txt";
  char sBuff[200];

  /* Try to open */
  if ( (TextFile = fopen(sFileName,"r")) == NULL)
  {
    /* File cannot be opened */
    //return -1;
  }
 
  while ( !(feof(TextFile) || ferror(TextFile)) )
  {
    /* Read a line into sBuff */
    fgets(sBuff, sizeof(sBuff), TextFile);
   
    /* Place your code here */

  }
 
  /* Close file */
  fclose(TextFile);

Ok thanks people, the file lines are not the same length... I will give Dharius code a try though it looks promising. I will let you know if i have problems,

Thanks
TNT

Hey i got the code to work, and the file is added line by line into the list box. I havnt used listboxes for a while and am having a few problems.

How do i erase all the strings from the listbox. Also how do i get the curret selected string into a buffer.

Thanks for the help
TNT

Use the LB_RESETCONTENT message to erase everything.

Get the string form of the current selection first by making sure something is selected, getting the item's index (LB_GETCURSEL), and using that value with LB_GETTEXT.

I use SetWindowText() on the edit box to clear it.....

Always worked.......

Anyway.......

I tried what you wanted by simply sucking up the data and using SetWindowText() again to load it into the edit control......it didnt work, cuz each line end needs '\r\n' instead of just '\r'....so I went back to the tokeniser and did this

Code:

void File2Display(HWND hEdit,char* szFile){

HANDLE hFile;
DWORD dwSize,dwReadSize;
char *lpBuffer = 0,
		*strPtr; //A pointer which is the return of strtok()
int x = 0;
string data("");

hFile = CreateFile(szFile,GENERIC_READ,0, NULL,OPEN_EXISTING,
		 FILE_ATTRIBUTE_NORMAL,
		 NULL); //Open File for reading

if(hFile == INVALID_HANDLE_VALUE){
		MessageBox(0,"Error with file","Error",MB_OK);
		return;
}

dwSize = GetFileSize(hFile,NULL);//Get the size of the file
lpBuffer = (char*)GlobalAlloc(0,dwSize+1); //Create a read in buffer

if(!lpBuffer){
MessageBox(0,"Error with memory allocation","Error",MB_OK);
        CloseHandle(hFile);
        return;	
}

ReadFile(hFile,lpBuffer,dwSize + 1,&dwReadSize,NULL);//Suck up file contents to buffer
lpBuffer[(int)dwSize] = '\0';

strPtr = strtok(lpBuffer,"\n");//Set Strtok to beginning of strcopy. Use '\n' for delimiter

while(strPtr){//while token is not NULL and less than total tokens
data += strPtr;//Copy token into buffer array
data += "\r\n";
strPtr = strtok(NULL,"\n");//Force strtok up the string
x++;
}

SetWindowText(hEdit,data.c_str());
GlobalFree(lpBuffer);//free memory
CloseHandle(hFile);//close file
}

If you use this as a general function, it should work....well I tried it and it worked fine....

Just send the function the HWND from the edit control, and a string saying the name of the file.......

>>I use SetWindowText() on the edit box to clear it.....

Right, which would be absolutely perfect if he were working with edit boxes, wouldn't it?


The easiest way to put the file in the listbox is with ANSI C. Trust me. I've tried both ways.

As for getting the selection...::digs up old code::

Code:

int index; //Index for the currently selected line.
char Buffer[MAX]; //Buffer to hold the data
...		
 if(LOWORD(wParam) == ID_LIST && HIWORD(wParam) == LBN_DBLCLK){
     index = SendMessage(hwndList, LB_GETCURSEL, 0, 0);
     SendMessage(hwndList, LB_GETTEXT, index, (LPARAM)Buffer);
}

>>I use SetWindowText() on the edit box to clear it.....

Right, which would be absolutely perfect if he were working with edit boxes, wouldn't it?

Gah.......Damn......now I have read it properly, I can see that....

Doh....I need glasses....