Thread: Create new combo boxes based on items selected in preview combo box

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Code:

#pragma comment( lib, "user32.lib" ) 

#include <windows.h>
#include <string.h>

#define ID_LIST 1
#define ID_TEXT 2

LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

char szClassName[ ] = "ComboBox App";


int WINAPI WinMain (HINSTANCE hThisInstance,
					HINSTANCE hPrevInstance,
					LPSTR lpszArgument,
					int nCmdShow)
{
	HWND hwnd;             
	MSG messages;          
	WNDCLASSEX wincl;      
	wincl.hInstance = hThisInstance;
	wincl.lpszClassName = szClassName;
	wincl.lpfnWndProc = WindowProcedure;    
	wincl.style = CS_DBLCLKS;               
	wincl.cbSize = sizeof (WNDCLASSEX);
	wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
	wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
	wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
	wincl.lpszMenuName = NULL;              
	wincl.cbClsExtra = 0;                   
	wincl.cbWndExtra = 0;                   
	wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
	if (!RegisterClassEx (&wincl))
		return 0;
	hwnd = CreateWindowEx (
		0,                 
		szClassName,       
		"ComboBox App",     
		WS_OVERLAPPEDWINDOW, 
		CW_USEDEFAULT,       
		CW_USEDEFAULT,       
		544,                 
		375,                 
		HWND_DESKTOP,       
		NULL,               
		hThisInstance,      
		NULL                
		);
	ShowWindow (hwnd, nCmdShow);

	while (GetMessage (&messages, NULL, 0, 0))
	{
		TranslateMessage(&messages);
		DispatchMessage(&messages);
	}
	return messages.wParam;
}

void FillListBox(HWND hwndList, DWORD items)
{
	TCHAR *pVarName1[] = {"Yes", "No"};
	TCHAR *pVarName2[] = {"Yes_1","No_1" };
	TCHAR *pVarName3[] = {"No_1_Second", "No_2_Second","No_3_second", "Go to Finished" };
	TCHAR *pVarName4[] = {"Yes_1_Second", "Yes_2_Second","Yes_3_Second", "Go to Finished" };
	TCHAR *pVarName5[] = {"Terminate App", "Go Back to Start"};
	switch(items)
	{
		case 1:
			SendMessage( hwndList, CB_RESETCONTENT, 0, 0 );
			for(int i=0; i<2; i++)
				SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName1[i]);
			SendMessage(hwndList, CB_SETCURSEL, 0, 0);
			break;
		case 2:
			SendMessage( hwndList, CB_RESETCONTENT, 0, 0 );
			for(int i=0; i<2; i++)
				SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName2[i]);
			SendMessage(hwndList, CB_SETCURSEL, 0, 0);
			break;
		case 3:
			SendMessage( hwndList, CB_RESETCONTENT, 0, 0 );
			for(int i=0; i<4; i++)
				SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName3[i]);
			SendMessage(hwndList, CB_SETCURSEL, 0, 0);
			break;
		case 4:
			SendMessage( hwndList, CB_RESETCONTENT, 0, 0 );
			for(int i=0; i<4; i++)
				SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName4[i]);
			SendMessage(hwndList, CB_SETCURSEL, 0, 0);
			break;
		case 5:
			SendMessage( hwndList, CB_RESETCONTENT, 0, 0 );
			for(int i=0; i<2; i++)
				SendMessage(hwndList, CB_ADDSTRING, 0, (LPARAM)pVarName5[i]);
			SendMessage(hwndList, CB_SETCURSEL, 0, 0);
			break;
		default:
			break;
	}
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static HWND hwndList, hwndText;
	int iIndex, iLength, cxChar, cyChar;
	TCHAR pVarName[30];
	switch (message)                  /* handle the messages */
	{
		case WM_CREATE:
			cxChar = LOWORD(GetDialogBaseUnits());
			cyChar = HIWORD(GetDialogBaseUnits());
			hwndText = CreateWindow(TEXT("static"),NULL, WS_CHILD | WS_VISIBLE |
				SS_LEFT, cxChar, cyChar, 
				GetSystemMetrics(SM_CXSCREEN), cyChar, 
				hwnd, (HMENU)ID_TEXT, 
				(HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), 
				NULL);
			hwndList =  CreateWindow(TEXT("Combobox"), NULL, WS_CHILD | WS_VISIBLE |
				LBS_STANDARD, cxChar, cyChar*3, 
				cxChar*16 + GetSystemMetrics(SM_CXVSCROLL), 
				cyChar*5, hwnd, (HMENU)ID_LIST, 
				(HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
				NULL);
			FillListBox(hwndList, 1);

			GetWindowText(hwndList, pVarName, 30);
			SetWindowText(hwndText, pVarName);
			return 0;

		case WM_COMMAND:

			if( LOWORD(wParam)==ID_LIST && HIWORD(wParam)==CBN_SELCHANGE)
			{
				GetWindowText(hwndList, pVarName, 30);      
				if( strcmp(pVarName,"Yes") == 0)
				{
					SetWindowText(hwndText, pVarName);
					FillListBox(hwndList, 2);
				}
				else if( strcmp(pVarName,"No") == 0)
				{
					SetWindowText(hwndText, pVarName);
					FillListBox(hwndList, 3);
				}
				else if( strcmp(pVarName,"Yes_1") == 0)
				{
					SetWindowText(hwndText, pVarName);
					FillListBox(hwndList, 4);
				}
				else if( strcmp(pVarName,"Go to Finished") == 0)
				{
					SetWindowText(hwndText, pVarName);
					FillListBox(hwndList, 5);
				}
				else if( strcmp(pVarName,"Go Back to Start") == 0)
				{
					SetWindowText(hwndText, pVarName);
					FillListBox(hwndList, 1);
				}
				else if( strcmp(pVarName,"Terminate App") == 0)
				{
					SetWindowText(hwndText, "App to be terminated");        
					MessageBox(NULL, "We Will Terminate App", "TERMINATE", MB_OK);
					PostQuitMessage (0);  
				}
				else    SetWindowText(hwndText, pVarName);
			}   
			return 0;    

		case WM_DESTROY:
			PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
			break;
		default: 
			return DefWindowProc (hwnd, message, wParam, lParam);
	}
	return 0;
}