C++(WINAPI - WIN32) Second edit box can't read the input value - c++

Question

I have two edit boxes. The first edit box read the input but the second edit box for some reason gives me an empty value. I have checked the windows handle value which is not NULL. What am I supposed to do because I am very very new with GUI programming. I hope you guys can help.
#include <windows.h>
#include "GUI.h"
#include <iostream>
#include <vector>
#include <cstdio>
using namespace std;
//#include "main.h"
const char g_szClassName[] = "myWindowClass";
HWND btObj[1], lblObj, lbl2Obj, hEdit1, hEdit2;
void CreateObjects(HWND hWnd)
{
//Buttons
btObj[0] = CreateWindow(TEXT("button"), //lpClassName = type of window to create
TEXT("Process"), //lpWindowName = Name that appears on the button
WS_VISIBLE | WS_CHILD, //dwStyle = Window style flags
140, 90, // x and y coordinates of the button in pixels
105, 33, //width and height of the button in pixels
hWnd, //hWndParent = handle of the parent or main window
(HMENU)1, //Menu item ID = 1
NULL, NULL); //Set the last 2 params as null
//Labels
lblObj = CreateWindow(TEXT("edit"),
TEXT("File Input: "),
WS_VISIBLE | WS_CHILD,
16, 16,
490, 25,
hWnd,
(HMENU)2,
NULL, NULL);
//Textbox
hEdit1 = CreateWindowEx(WS_EX_CLIENTEDGE,
"EDIT", "",
WS_CHILD | WS_VISIBLE | ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
100, 16,
200, 25,
hWnd,
(HMENU)IDC_MAIN_INPUT,
GetModuleHandle(NULL), NULL);
//Labels
lbl2Obj = CreateWindow(TEXT("edit"),
TEXT("File Output: "),
WS_VISIBLE | WS_CHILD,
16, 55,
510, 40,
hWnd,
(HMENU)4,
NULL, NULL);
//Textbox number 2
hEdit2 = CreateWindowEx(WS_EX_CLIENTEDGE,
"EDIT", "",
WS_CHILD | WS_VISIBLE | ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
100, 55,
200, 25,
hWnd,
(HMENU)IDC_MAIN_OUTPUT,
GetModuleHandle(NULL), NULL);
}
// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_COMMAND:
switch (LOWORD(wParam))
{
case IDC_MAIN_BUTTON:
//HWND inputFile, outputFile;
TCHAR inFile[30];
TCHAR outFile[30];
//TEXTBOX 1
HWND hEditWnd;
hEditWnd = GetDlgItem(hwnd, IDC_MAIN_INPUT);
HWND hEditWnd2;
hEditWnd2 = GetDlgItem(hwnd, IDC_MAIN_OUTPUT);
GetWindowText(hEditWnd,inFile, 30);
SetDlgItemTextA(hwnd, IDC_MAIN_INPUT, inFile);
if (hwnd == NULL)
{
MessageBox(NULL, "This hwnd is NULL Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
else
{
MessageBox(NULL, "This hwnd has some value", "Error!", MB_ICONEXCLAMATION | MB_OK);
}
SetFocus (hEdit2);
GetWindowText(hEditWnd2,outFile, 30);
SetDlgItemTextA(hwnd, IDC_MAIN_OUTPUT, outFile);
MessageBox(NULL, inFile, "TESTING", MB_OK);
MessageBox(NULL, outFile, "TESTING", MB_OK);
}
break;
case WM_CREATE:
CreateObjects(hwnd);
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"CSV Converter",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
390, 200,
NULL, NULL,
hInstance, NULL);
if (hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: The Message Loop
while (GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}

Answer 1

hEditWnd = GetDlgItem(hwnd, IDC_MAIN_INPUT);
...
GetWindowText(hEditWnd,inFile, 30);
SetDlgItemTextA(hwnd, IDC_MAIN_INPUT, inFile);
You are retreiving the inFile value from the IDC_MAIN_INPUT control, and then assigning the inFile value back to the same IDC_MAIN_INPUT control.
hEditWnd2 = GetDlgItem(hwnd, IDC_MAIN_OUTPUT);
...
GetWindowText(hEditWnd2,outFile, 30);
SetDlgItemTextA(hwnd, IDC_MAIN_OUTPUT, outFile);
You are retreiving the outFile value from the IDC_MAIN_OUTPUT control, and then assigning the outFile value back to the same IDC_MAIN_OUTPUT control.
The end result: you don't see any change in the UI, because you did not actually change anything!