C / C++ / MFC

public:
	//{{AFX_DATA(MyDlg)
	enum { IDD = IDD_TEST_FORM };
	CEdit	m_Edit1;
	CString	m_sEdit1;
	//}}AFX_DATA

void MyDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(MyDlg)
	DDX_Control(pDX, IDC_EDIT1, m_Edit1);
	DDX_Text(pDX, IDC_EDIT1, m_sEdit1);
	//}}AFX_DATA_MAP
}

void MyDlg::OnEnchangeEdit()
{
   updateData(FALSE);
   Function(1st parameter, m_sEdit1);
}

Member 14575556 wrote:

m_Edit.GetWindowTextW(temp);

GetDlgItem(IDC_MYBUTTON)->ShowWindow(GetDlgItem(<your_listcontrol_ID>)->GetSelectedCount() > 0);

1. Do it "live" as the user types in value (mostly with the EN_CHANGE message); each time the user types something, use GetWindowText and start searching the Database; this is somewhat complicated as the search can take a long time compared to the speed the user types (you would need some way to stop the current search and start a new one each time a new character is typed in); warn the user with visual feedback (red highlights while the input is not valid.
2. Do it when the user clicks on the "ok" (or "search") button; on the OnOK (or "search") , get the full string with GetWindowText and do some validation and search the Database; easier to implement, you can just wait for the whole search to be done and warn user after with a simple SetWindowText to your static control (or edit control) that will display the error.

Erich Ruth wrote:

Sometimes I can make
the software edit this file but many times it doesnt work.