API | MFC | C++ | C |
Programming Windows API

RadioButton Control Example

//radiobutton demo

#include <windows.h>

#define ID_BLUE 1

#define ID_YELLOW 2

#define ID_RED 3

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



HINSTANCE hInstance;

COLORREF bk_color;



int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,PWSTR lpCmdLine, int nCmdShow) {



HWND hwnd;

MSG msg ; 

WNDCLASS wc = {0};

wc.lpszClassName = TEXT("myWindowClass");

wc.hInstance = hInstance;

wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);

wc.lpfnWndProc = WndProc;

wc.hCursor = LoadCursor(0, IDC_ARROW);

hInstance = hInstance;

RegisterClass(&wc);

hwnd = CreateWindow(wc.lpszClassName, TEXT("RadioButton Demo"),WS_OVERLAPPEDWINDOW | WS_VISIBLE,100, 100, 410, 170, 0, 0, hInstance, 0); 



while( GetMessage(&msg, NULL, 0, 0)) {

DispatchMessage(&msg);

}



return (int) msg.wParam;

}



LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, 

WPARAM wParam, LPARAM lParam) {

PAINTSTRUCT ps;

HBRUSH hBrush;

switch(msg) {



case WM_CREATE:



bk_color = RGB(255, 255, 255);

/*create grouping box and associated buttons.*/

CreateWindow(TEXT("button"), TEXT("Choose colour"), WS_CHILD | WS_VISIBLE | BS_GROUPBOX,50,25,300,70, hwnd, (HMENU) 0, hInstance, NULL);

CreateWindow(TEXT("button"), TEXT("Blue"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,70,50,75,30, hwnd, (HMENU) ID_BLUE , hInstance, NULL);

CreateWindow(TEXT("button"), TEXT("Yellow"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,145,50,85,30, hwnd, (HMENU) ID_YELLOW , hInstance, NULL);

CreateWindow(TEXT("button"), TEXT("Red"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,230,50,75,30, hwnd, (HMENU) ID_RED , hInstance, NULL);

break;



case WM_COMMAND:

/*responds to button click by setting variable bk_color to value of colour associated with radio button */

if (HIWORD(wParam) == BN_CLICKED) {

switch (LOWORD(wParam)) {

case ID_BLUE:

bk_color = RGB(0, 76, 255);

break;

case ID_YELLOW:

bk_color = RGB(255, 255, 0);

break;

case ID_RED:

bk_color = RGB(255, 0, 0);

break;

}

HDC hdc;

hdc=GetDC(hwnd);

SetBkColor(hdc,bk_color);

RECT theRect;

GetClientRect(hwnd, &theRect);

InvalidateRect(hwnd,&theRect,TRUE);

ReleaseDC(hwnd,hdc);

DeleteDC(hdc);

}

break;



case WM_PAINT:

/*set background of window to colour selected by radiobutton selection ie red blue or yellow*/

HDC hdc;

hdc = BeginPaint(hwnd, &ps);

hBrush = CreateSolidBrush(bk_color);

RECT theRect;

GetClientRect(hwnd, &theRect);

FillRect(hdc, &theRect, hBrush);

DeleteObject(hBrush);

EndPaint(hwnd, &ps);

ReleaseDC(hwnd,hdc);

DeleteDC(hdc);

break;



case WM_DESTROY:

PostQuitMessage(0);

break; 

}



return DefWindowProc(hwnd, msg, wParam, lParam);

}