Opening a file and writing to Text box c++ - c++

Question

Okay, so I need this button that, when clicked, opens a user-specified file. After the file is opened, it needs to be read/copied into the text box below that button. Eventually other things need to happen but I'm having trouble just doing that. The following is the code I have so far for creating the GUI, then I'm completely lost on how to proceed.
#include <iostream>
#include <fstream>
#include <windows.h>
/* Declare Windows procedure */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
/* Make the class name into a global variable */
char szClassName[ ] = "WindowsApp";
int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nFunsterStil)
{
HWND hwnd; /* This is the handle for our window */
MSG messages; /* Here messages to the application are saved */
WNDCLASSEX wincl; /* Data structure for the windowclass */
/* The Window structure */
wincl.hInstance = hThisInstance;
wincl.lpszClassName = szClassName;
wincl.lpfnWndProc = WindowProcedure; /* This function is called by windows */
wincl.style = CS_DBLCLKS; /* Catch double-clicks */
wincl.cbSize = sizeof (WNDCLASSEX);
/* Use default icon and mouse-pointer */
wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName = NULL; /* No menu */
wincl.cbClsExtra = 0; /* No extra bytes after the window class */
wincl.cbWndExtra = 0; /* structure or the window instance */
/* Use Windows's default color as the background of the window */
wincl.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
/* Register the window class, and if it fails quit the program */
if (!RegisterClassEx (&wincl))
return 0;
/* The class is registered, let's create the program*/
hwnd = CreateWindowEx (
0, /* Extended possibilites for variation */
szClassName, /* Classname */
"Software Engineering II", /* Title Text */
WS_SYSMENU | WS_MINIMIZEBOX | WS_MAXIMIZEBOX, /* default window */
CW_USEDEFAULT, /* Windows decides the position */
CW_USEDEFAULT, /* where the window ends up on the screen */
900, /* The programs width */
500, /* and height in pixels */
HWND_DESKTOP, /* The window is a child-window to desktop */
NULL, /* No menu */
hThisInstance, /* Program Instance handler */
NULL /* No Window Creation data */
);
/* Make the window visible on the screen */
ShowWindow (hwnd, nFunsterStil);
/* Run the message loop. It will run until GetMessage() returns 0 */
while (GetMessage (&messages, NULL, 0, 0))
{
/* Translate virtual-key messages into character messages */
TranslateMessage(&messages);
/* Send message to WindowProcedure */
DispatchMessage(&messages);
}
/* The program return-value is 0 - The value that PostQuitMessage() gave */
return messages.wParam;
}
#define ID_LABEL
static HWND hwndLbl1;
static HWND hwndLbl2;
static HWND hwndLbl3;
static HWND hwndLbl4;
bool buttonPressed = false;
/* This function is called by the Windows function DispatchMessage() */
LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message) /* handle the messages */
{
case WM_CREATE:
hwndLbl1 = CreateWindow(TEXT("STATIC"),TEXT("Building File Selection"),
WS_VISIBLE | WS_CHILD,
10,10,150,25,
hwnd, (HMENU) 0, NULL, NULL
);
hwndLbl2 = CreateWindow(TEXT("STATIC"),TEXT("Class File Selection"),
WS_VISIBLE | WS_CHILD,
500,10,150,25,
hwnd, (HMENU) 0, NULL, NULL
);
hwndLbl3 = CreateWindow(TEXT("STATIC"),TEXT("Building No."),
WS_VISIBLE | WS_CHILD,
10, 75, 150, 25,
hwnd, (HMENU) 0, NULL, NULL
);
hwndLbl4 = CreateWindow(TEXT("STATIC"),TEXT("Room No."),
WS_VISIBLE | WS_CHILD,
500,75,150,25,
hwnd, (HMENU) 0, NULL, NULL
);
// Building Room open
CreateWindow(TEXT("button"),TEXT("Open"),
WS_VISIBLE | WS_CHILD,
10,40,80,25,
hwnd, (HMENU) 1, NULL, NULL
);
// Classroom open
CreateWindow(TEXT("button"),TEXT("Open"),
WS_VISIBLE | WS_CHILD,
500, 40, 80, 25,
hwnd, (HMENU) 2, NULL, NULL
);
CreateWindow(TEXT("button"),TEXT("Search"),
WS_VISIBLE | WS_CHILD,
800,100,80,25,
hwnd, (HMENU) 3, NULL, NULL
);
// The information should be read from here.
CreateWindow(TEXT("edit"), TEXT("Text goes here"),
WS_VISIBLE | WS_CHILD | WS_BORDER,
10, 100, 300, 20,
hwnd, (HMENU) 5, NULL, NULL
);
CreateWindow(TEXT("edit"),TEXT("Text goes here"),
WS_VISIBLE | WS_CHILD | WS_BORDER,
500,100,300,20,
hwnd, (HMENU) 5, NULL, NULL
);
CreateWindow(TEXT("edit"),TEXT("Output from Building"),
WS_CHILD | WS_VISIBLE | ES_READONLY | WS_BORDER,
10, 150, 400, 250,
hwnd, (HMENU) 6, NULL, NULL
);
CreateWindow(TEXT("edit"),TEXT("Output from Room file"),
WS_CHILD | WS_VISIBLE | ES_READONLY | WS_BORDER,
500, 150, 380, 250,
hwnd, (HMENU) 7, NULL, NULL
);
CreateWindow(TEXT("button"),TEXT("Continue"),
WS_VISIBLE | WS_CHILD,
500,410,80,25,
hwnd, (HMENU) 8, NULL, NULL
);
CreateWindow(TEXT("button"),TEXT("Show .PRN"),
WS_VISIBLE | WS_CHILD,
600,410,80,25,
hwnd, (HMENU) 9, NULL, NULL
);
CreateWindow(TEXT("button"),TEXT("Show .LOG"),
WS_VISIBLE | WS_CHILD,
700,410,80,25,
hwnd, (HMENU) 10, NULL, NULL
);
CreateWindow(TEXT("button"),TEXT("Show .CSV"),
WS_VISIBLE | WS_CHILD,
800,410,80,25,
hwnd, (HMENU) 11, NULL, NULL
);
break;
// This is where you issue commands for buttons
// To read from files and output them into those 2 text boxes that are ID'd (HMENU) 6 and (HMENU 7.
case WM_COMMAND:
if(LOWORD(wParam) == 1){
FILE * BuildingFile;
buttonPressed = true;
/* ifstream infile;
infile.open ("Bldgs-Rms-Txt-File-2012-08082012.txt");
if(infile.is_open()){
while(infile.good())
print to buildingtextbox (char) infile.get();
//BuildingFile = fopen("Bldgs-Rms-Txt-File-2012-08082012.txt","r"); // In the argument of MessageBox, this is the PARENT WINDOW, which should be the same for all
*/
}
if (LOWORD (wParam) == 2){
FILE * RoomFile;
RoomFile = fopen("cbm_005_003639_201310_08082012.DAT","r");
}
if (LOWORD (wParam) == 6){
std::cout << "chuck";
}
break;
case WM_DESTROY:
PostQuitMessage (0); /* send a WM_QUIT to the message queue */
break;
default: /* for messages that we don't deal with */
return DefWindowProc (hwnd, message, wParam, lParam);
}
return 0;
}

Answer 1

1) You need to preserve the window handles (hWnd)s from the CreateWindow calls.
// Up top
#include <string>
// Class member:
HWND building1text;
// Saving the hWnd on the CreateWindow call
building1text = CreateWindow(TEXT("edit"),TEXT("Output from Building"),
WS_CHILD | WS_VISIBLE | ES_READONLY | WS_BORDER,
10, 150, 400, 250,
hwnd, (HMENU) 6, NULL, NULL
);
2) Then you can use SetWindowText(hWnd, LPCTSTR) to put the text into the text box.
string lineString, totalString;
// open file here
while(infile.good()) {
// concatenate next line from file (works if file contains
// null-terminated lines of stuff
getline(infile, lineString, '\n');
totalString += lineString;
}
SetWindowText(building1text, totalString);
I don't have a compiler set up, but hopefully that works for you. Of course, I don't know how your data file is formatted, either.