GetWindowtext returning nothing - c++

Question

I'm trying to learn how to make a GUI for a C++ using visual studio. I’ trying to create a button that when you push it a textbox with the content of a edit window appear, but the GetWindowText function is Returning a blank string when I run my program. I have tried to adjust the size of the buffer to see if that is the problem, but I haven’t been able to solve it that way. I have tried using number instead of the GetWindowTextLength() funktion, but I could not get it to work that way.
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
{` HMENU hMenubar = CreateMenu();
HMENU hFile = CreateMenu();
HMENU hOptions = CreateMenu();
AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hFile, L"File");
AppendMenu(hMenubar, MF_POPUP, NULL, L"Edit");
AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hOptions, L"Options");
AppendMenu(hFile, MF_STRING, NULL, L"Exit");
AppendMenu(hOptions, MF_STRING, NULL, L"option 1");
AppendMenu(hOptions, MF_STRING, NULL, L"option 2");
SetMenu(hWnd, hMenubar);
CreateWindow(TEXT("button"), TEXT("Hello"),
WS_VISIBLE | WS_CHILD,
10, 10, 80, 25,
hWnd, (HMENU) ID_BUTTON1, NULL, NULL);
static HWND hWndTextbox = CreateWindow(TEXT("edit"), TEXT("sim"),
WS_VISIBLE | WS_CHILD|WS_BORDER | ES_AUTOHSCROLL,
90, 120, 300, 20,
hWnd, (HMENU) ID_TEXT3, NULL, NULL);
CreateWindow(TEXT("button"), TEXT("shiny"),
WS_VISIBLE | WS_CHILD,
50, 50, 80, 50,
hWnd, (HMENU) ID_BUTTON2, NULL, NULL);
}
break;
case WM_COMMAND:
{
if (LOWORD(wParam) == ID_BUTTON1) {
MessageBox(hWnd, TEXT("Button has been clicked"), TEXT("title for popup"), MB_ICONINFORMATION);
}
if (LOWORD(wParam) == ID_BUTTON2) {
// create some default vars
// Allocate buffer including terminating null
int length = GetWindowTextLength(hWndTextbox) + 1;
std::wstring uinput(GetWindowTextLength(hWndTextbox) + 1, 0);
// Address of first character is used to obtain pointer to non-const data
// (as opposed to wstring::c_str()).
int size = GetWindowText(hWndTextbox, &uinput[0], length+1);
// Resize buffer to the actual text length
uinput.resize(size);
// MessageBox only needs pointer to const string, so we can use wstring::c_str() here.
MessageBox(hWnd, uinput.c_str(), TEXT("Message box"), MB_OK);
}
break;
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}`
the rest of the code was auto generated by visual studio so I have only included the part where I made changes