Window Edit Control Not Displaying - windows

Question

Here is my code. I'm trying to create an edit control. It's not showing, however. Can some take a look at my code and point out the errors please. I can't figure out where the error is. I feel It might have something to do with the parent child relationship.
#include <cstdlib>
#include <windows.h>
#define MAINWINDOW_CLASS_ID 140;
const char* MAINWINDOW_CLASS_NAME = "Main Window";
const char* TEXTAREA_CLASS_NAME = "EDIT";
using namespace std;
LRESULT CALLBACK WinProc(HWND hwnd, UINT uMsg,
WPARAM wParam, LPARAM lParam);
/*
* Initialize the window class and register it.
*/
BOOL initInstance(HINSTANCE hInstance);
/*
* Create and show the window
*/
HWND initWindow(HINSTANCE hInstance);
HWND createTextArea(HWND hParent);
/*
*
*/
INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hprevInstance, LPSTR lpCmdline, INT cmdlShow)
{
if (!initInstance(hInstance))
return 0;
HWND hwndMain = initWindow(hInstance);
ShowWindow(hwndMain, cmdlShow);
MSG msg = {} ;
while (GetMessage(&msg, NULL, 0, 0)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return 0;
}
BOOL initInstance(HINSTANCE hInstance)
{
WNDCLASS wc = {};
wc.lpfnWndProc = WinProc;
wc.hInstance = hInstance,
wc.lpszClassName = MAINWINDOW_CLASS_NAME;
return RegisterClass(&wc);
}
HWND initWindow(HINSTANCE hInstance)
{
HWND hwndMain = CreateWindow(
MAINWINDOW_CLASS_NAME, // The class name
"Text Editor", // The window name
WS_OVERLAPPEDWINDOW,// The window style
CW_USEDEFAULT, // The x pos
CW_USEDEFAULT, // The y pos
CW_USEDEFAULT, // The width
CW_USEDEFAULT, // The height
(HWND) NULL, // Handle to parent
(HMENU) NULL, // Handle to the menu
hInstance, // Handle to the instance
NULL // Window creation data
);
if (!hwndMain) {
return NULL;
}
else {
return hwndMain;
}
}
LRESULT CALLBACK WinProc(HWND hwnd, UINT uMsg,
WPARAM wParam, LPARAM lParam) {
HWND htextArea;
char sztestText[] = "I should be able to see this text.";
switch (uMsg) {
case WM_CREATE:
htextArea = createTextArea(hwnd);
SendMessage(htextArea, WM_SETTEXT, 0, (LPARAM) sztestText);
break;
case WM_PAINT:
break;
case WM_CLOSE:
break;
case WM_SIZE:
RECT rectMainWindow;
GetWindowRect(hwnd, &rectMainWindow);
INT x = rectMainWindow.right - rectMainWindow.left + 50;
INT y = rectMainWindow.bottom - rectMainWindow.top + 50;
MoveWindow(htextArea, 0, 0, x, y, TRUE);
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
/*******************************************************************/
HWND createTextArea(HWND hParent) {
return CreateWindow(
TEXTAREA_CLASS_NAME, // Class control name
NULL, // Title
WS_CHILD | WS_VISIBLE | ES_MULTILINE, // Styles
0, 0, 0, 0, // Sizing and position
hParent,
(HMENU) MAKEINTRESOURCE(100),
(HINSTANCE) GetWindowLong(hParent, GWL_HINSTANCE),
NULL
);
}

Answer 1

You've defined htextArea as a local variable in WinProc and so every time your window procedure is called its value will be uninitialized. You should make it static or move it to global data outside the function.
(The actual problem is that when you get a WM_SIZE message, you've lost the handle to the edit control, and so its size remains as 0,0).