How to implement SendKeys in C/C++

I'm developing a 16-bit Windows app.  I did a prototype in Visual Basic and used the SendKeys() function to send keystrokes to other applications.  Now I'm writing the real product using Visual C++ V1.52 and can't figure out how to do the SendKeys.  I've tried sending WM_CHAR, WM_KEYUP, WM_KEYDOWN messages without luck.

In particular, I'm putting a metafile on the clipboard and trying to paste it into another application.  In the prototype I just called SendKeys to send the Ctrl-Insert keystroke and it worked like a charm.

Can anyone please help me out????
fitzyAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

chensuCommented:
It should work. How do you get the window handle to which you would like to send the messages? Please note you should get the window handle that exactly processes key messages. For example, the edit window processes key messages instead of the main window does. The following tested code shows how to send the messages to Notepad.

    CWnd *pWnd = CWnd::FindWindow(NULL, "Untitled - Notepad");
    if (pWnd != NULL)
    {
        CWnd *pWndEdit = pWnd->GetWindow(GW_CHILD);
        if (pWndEdit != NULL)
        {
            pWndEdit->PostMessage(WM_KEYDOWN, VK_SPACE, 0x00390001UL);
            pWndEdit->PostMessage(WM_KEYUP, VK_SPACE, 0xC0390001UL);
            // or pWndEdit->PostMessage(WM_CHAR, VK_SPACE, 0x00390001UL);
           
            ::MessageBeep(-1);
        }
    }

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
fitzyAuthor Commented:
Recommending the call to GetWindow(GW_CHILD) was a good one and it did work with Notepad.  Unfortunately it does not work with other apps, though (e.g., Wordpad).  My  VB prototype  worked with everything I tried.  In the VB prototype I called
        AppActivate
then
        SendKeys

I need to make my app work with any destination application.  Do you have any recommendations?

Thanks!



0
chensuCommented:
I see. Since you need to make your app work with any destination application, it is not so easy. You can do something like the following code,

    CWnd *pWnd = CWnd::FindWindow(NULL, "Document - Wordpad");
    if (pWnd != NULL)
    {
        pWnd->SendMessageToDescendants(WM_CHAR, VK_SPACE, 0x00390001UL);
       
        ::MessageBeep(-1);
    }

Let me explain further. Because SendMessageToDescendants uses SendMessage instead of PostMessage and SendMessage(WM_KEYDOWN), SendMessage(WM_KEYDOWN) do not generate WM_CHAR message, I use WM_CHAR directly. You can choose appropriate method depending on your program. You can also refer to MFC source code to see how SendMessageToDescendants works. You might want to write your own PostMessageToDescendants.

Initially, I thought the following code was the best way.

    CWnd *pWnd = CWnd::FindWindow(NULL, "Document - Wordpad");
    if (pWnd != NULL)
    {
        pWnd->SetActiveWindow();
       
        CWnd *pWndEdit = CWnd::GetFocus();
       
        if (pWndEdit != NULL)
        {
            pWndEdit->PostMessage(WM_KEYDOWN, VK_SPACE, 0x00390001UL);
            pWndEdit->PostMessage(WM_KEYUP, VK_SPACE, 0xC0390001UL);
           
            ::MessageBeep(-1);
        }
       
        this->SetActiveWindow();
    }

It does work if the destination application is 16-bit too. Unfortunately, pWndEdit is NULL if the destination application is 32-bit. It is OK if your application runs under Windows 3.1 only.

0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft Development

From novice to tech pro — start learning today.