Question

Right now, I have a tool tip that pops up when I hover over an edit box. The problem is that this tool tip contains multiple error messages and they are all in one long line. I need to have each error message be on its own line. The error messages are contained in a CString with a new line seperating them.

My existing code is below.

BOOL OnToolTipText(UINT, NMHDR* pNMHDR, LRESULT* pResult) {     ASSERT(pNMHDR->code == TTN_NEEDTEXTA || pNMHDR->code == TTN_NEEDTEXTW);     // need to handle both ANSI and UNICODE versions of the message     TOOLTIPTEXTA* pTTTA = (TOOLTIPTEXTA*)pNMHDR;     TOOLTIPTEXTW* pTTTW = (TOOLTIPTEXTW*)pNMHDR;     //    TCHAR szFullText[256];     CString strTipText=_T('');     UINT nID = pNMHDR->idFrom;     if (pNMHDR->code == TTN_NEEDTEXTA && (pTTTA->uFlags & TTF_IDISHWND) ||         pNMHDR->code == TTN_NEEDTEXTW && (pTTTW->uFlags & TTF_IDISHWND))     {         // idFrom is actually the HWND of the tool         nID = ::GetDlgCtrlID((HWND)nID);     }      //m_errProjAccel[ch] contains 1 or more error messages each seperated by a new line.     if((int)nID >= ID_PROJECTED_ACCEL1 && (int)nID < ID_PROJECTED_ACCEL1 + PROJECTED_ROWS -1 ) {         int ch = nID - ID_PROJECTED_ACCEL1;         strTipText = m_errProjAccel[ch];     }    #ifndef _UNICODE     if (pNMHDR->code == TTN_NEEDTEXTA)         lstrcpyn(pTTTA->szText, strTipText, sizeof(pTTTA->szText)/sizeof(pTTTA->szText[0]));     else         _mbstowcsz(pTTTW->szText, strTipText, sizeof(pTTTA->szText)/sizeof(pTTTA->szText[0])); #else     if (pNMHDR->code == TTN_NEEDTEXTA)         _wcstombsz(pTTTA->szText, strTipText, sizeof(pTTTA->szText)/sizeof(pTTTA->szText[0]));     else         lstrcpyn(pTTTW->szText, strTipText, sizeof(pTTTA->szText)/sizeof(pTTTA->szText[0])); #endif     *pResult = 0;      // bring the tooltip window above other popup windows     ::SetWindowPos(pNMHDR->hwndFrom, HWND_TOP, 0, 0, 0, 0,         SWP_NOACTIVATE|SWP_NOSIZE|SWP_NOMOVE|SWP_NOOWNERZORDER);      return TRUE;    // message was handled } 

Answer 1

Creating multiline tooltips is explained here in the MSDN library – read the ‘Implementing Multiline ToolTips’ section. You should send a TTM_SETMAXTIPWIDTH message to the ToolTip control in response to a TTN_GETDISPINFO notification to force it to use multiple lines. In your string you should separate lines with \r\n.

Also, if your text is more than 80 characters, you should use the lpszText member of the NMTTDISPINFO structure instead of copying into the szText array.