Autodesk ObjectARX

[#1]

How can I ask for a password, replacing each keystroke with a generic character, on the command line of AutoCAD 2013 using ObjectARX?

Thanks in advance.

[#2]

Try this: http://adndevblog.typepad.com/autocad/2012/06/asking-for-a-password-on-the-command-line-of-autocad-u...

[#3]

Thanks Alexander, but the solution in adndevblog fails in AutoCAD 2013. Look the comment by Thierry Prince below the solution.

[#4]

Hi Jose,

Using hooks is a hack that is not generally advisable to use. If you have the option, switch over to a UI to take that input which you are trying to mask. That way you will not need to use hooks.

However if you still need to go this route, then here is a code snippet based on the low level keyboard hooks. Hope this helps. I havent tested it very extensively but seems to work in general using AutoCAD 2013.

Here is the sample code :

static ACHAR password[133]; 
static int pwdLen; 
static HHOOK hKeyboardHook;

// - AdskMyTest1.MyCommand1 command (do not rename)
static void AdskTestCommand(void)
{
	ACHAR pwd[133];   
	adskGetPassword(1, ACRX_T("Password please ?"), pwd);	
}

static int adskGetPassword(int cronly,ACHAR* prompt,ACHAR* result)
{
	pwdLen = 0;
	password[pwdLen]='\0';
	HINSTANCE hInstance = GetModuleHandle(NULL);
	if (!hInstance) 
		return 1;

	hKeyboardHook = SetWindowsHookEx ( 
										WH_KEYBOARD_LL, 
										(HOOKPROC) KeyboardEvent, 
										hInstance, 
										NULL 
										);
		
	ACHAR tempResult[133];
	int ret = acedGetString(cronly, prompt, tempResult);

	UnhookWindowsHookEx(hKeyboardHook);

	if(ret != RTNORM)
		acutPrintf(ACRX_T("\nCancelled."));
	else
	{
		password[++pwdLen] = '\0';
		acutPrintf(password);
	}

	wcscpy(result, password);

	return ret;
}

static LRESULT CALLBACK KeyboardEvent (int nCode, WPARAM wParam, LPARAM lParam)
{
	if ((nCode == HC_ACTION) && 
	((wParam == WM_SYSKEYDOWN) || 
	(wParam == WM_KEYDOWN))) 
	{
		KBDLLHOOKSTRUCT hooked_key = *((KBDLLHOOKSTRUCT*)lParam);
		DWORD dwMsg = 1;
		dwMsg += hooked_key.scanCode << 16;
		dwMsg += hooked_key.flags << 24;
		int key = hs.vkCode;
		if ((key >= 'A' && key <= 'Z')  || (key >= '0' && key <= '9'))
		{
			GetKeyNameText(dwMsg, &password[pwdLen], 0xFF) + 1;
			password[++pwdLen] = '\0';
			keybd_event(VK_MULTIPLY, hooked_key.scanCode, hooked_key.flags, 0);
			return 1;
		}
		else if(hooked_key.vkCode == VK_BACK)
		{
			password[--pwdLen] = '\0';
		}
	}
	return CallNextHookEx(hKeyboardHook, nCode,wParam,lParam);
}

[#5 · Accepted solution]

Thanks Balaji for your reply. The code works well with some corrections:

The line

int key = hs.vkCode;

must be

int key = hooked_key.vkCode;

and the line

GetKeyNameText(dwMsg, &password[pwdLen], 0xFF) + 1;

must be

GetKeyNameText(dwMsg, &password[pwdLen], 0xFF);