how to get numeric value from edit control

Question

Sorry if this is too trivial, but I can't figure out how to get numeric value entered into edit control. MFC edit control represented by CEdit class.

Thank you.

Answer 1

CEdit derives from CWnd, so it has a member function called GetWindowText which you can call to get the text in the CEdit, and then convert that into numeric type, int or double - depending on what you expect user to enter:

CString text;
editControl.GetWindowText(text);

//here text should contain the numeric value
//all you need to do is to convert it into int/double/whatever

Answer 2

Besides the GetWindowText method already mentioned, you can also bind it via DDX to an integer/unsigned integer/double/float value. Try this:

void CYourAwesomeDialog::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    DDX_Text(pDX, IDC_EDIT_NUMBER, m_iNumber);
}

whereas m_iNumber is a member of your CYourAwesomeDialog class.

You have to call

UpdateData(TRUE);

in order to write the values from the controls into the variables. Call

UpdateData(FALSE);

to do it the other way around - from the variables in the controls.

EDIT (Bonus):

Upon re-reading my answer, I noticed that UpdateData(...) needs a BOOL variable - corrected. So I had an idea for people who like readability. Because I always got confused which call did which direction, you could introduce an enum to make it more readable, like so (maybe in stdafx.h or some central header):

enum UpdateDataDirection
{
    FromVariablesToControls = FALSE,
    FromControlsToVariables = TRUE
}

and you would just have to write:

UpdateData(FromVariablesToControls);

or

UpdateData(FromControlsToVariables);