How to check if a button is checkbox on 64 bit windows? - winapi

Question

I'm checking if a button is checkbox of 32bit process on 64bit windows10.
The problem is that I can not distingush checkbox from normal button.
The buttons are different in Window-Detective:
(After I restart the application, even Window-Detective shows it is a button now!)
But the checkbox can't be recognized as checkbox in Spy++
BS_CHECKBOX is not listed.
Code (compiled as 32bit):
TEST_METHOD(ShouldCheckStyle) {
auto styleOfButton = ::GetWindowLongPtr((HWND)0x003F06E8, GWL_STYLE);
auto styleOfCheckbox = ::GetWindowLongPtr((HWND)0x01101642, GWL_STYLE);
auto bsOfButton = styleOfButton & BS_TYPEMASK;
auto bsOfCheckbox = styleOfCheckbox & BS_TYPEMASK;
auto resultOfButton = (bsOfButton == BS_CHECKBOX);
auto resultOfCheckbox = (bsOfCheckbox == BS_CHECKBOX);
auto debugger = 0;
}
Debug output
The code indicates they both have BS_OWNERDRAW. The above behaves the same for the button and the checkbox.
The weird thing is Window-Detective can recognize the style of checkbox. The code is same as I used above. Here's a piece of code:
Window* WindowManager::createWindow(HWND handle) {
WindowClass* windowClass = getWindowClassFor(handle);
String className = windowClass->getName().toLower();
if (className == "button") {
LONG typeStyle = GetWindowLong(handle, GWL_STYLE) & BS_TYPEMASK;
switch (typeStyle) {
case BS_CHECKBOX:
case BS_AUTOCHECKBOX:
case BS_3STATE:
case BS_AUTO3STATE: {
return new CheckBox(handle, windowClass);
}
case BS_RADIOBUTTON:
case BS_AUTORADIOBUTTON: {
return new RadioButton(handle, windowClass);
}
case BS_GROUPBOX: {
return new GroupBox(handle, windowClass);
}
default: {
// If none of the above is true, then the control is just a Button
return new Button(handle, windowClass);
}
}
}

Answer 1

After some discussion, you can use GetWindowText to get the text from each control and compare the specific text.
BS_CHECKBOX cannot be detected from the properties of the "checkbox" control beacuse of BS_OWNERDRAW.
Creates an owner-drawn button. The owner window receives a WM_DRAWITEM
message when a visual aspect of the button has changed. Do not combine
the BS_OWNERDRAW style with any other button styles.
Try the below code:
WCHAR str1[20];
WCHAR str2[] = L"Agree me";
GetWindowText(hwnd_checkbox, str1, 256);
if (_tcscmp(str1, str2) == 0)
{
//it is checkbox
}
else
{
//it isn't checkbox
}
After you get the correct control handle of the checkbox, you can use SendDlgItemMessage or SendMessage to send BM_SETCHECK check message.
SendMessage(hwnd_checkbox, BM_SETCHECK, BST_CHECKED, 0);