Visual C++ and MFC Programming 2nd Edition

Chapter 16: Text-Based Controls Visual C++ and MFC Fundamentals

7. Return to MSVC

16.2.2..Edit Control Characteristics...............................................................

An edit box is a control based on the CEdit class. Therefore, to programmatically create

an edit box, declare a variable of CEdit type using its (default) constructor. To define the

characteristics of this control, you can call the CEdit::Create() method. Its syntax is:

BOOL Create(DWORD dwStyle, const RECT& rect, CWnd* pParentWnd, UINT nID);

The content of an edit box, that is, its value, is a string. It could be considered as null-

terminated constant (LPCTSTR) or a CString value.

Like every other control added during design, you should give some attention to the

identifier of an edit box. The first edit box placed on a form or dialog box receives an

identifier of IDC_EDIT1. The second would be identified as IDC_EDIT2, etc. It is highly

recommended that you give a meaningful and friendly identifier to each control. For

example, if an edit box is used to receive or display an address, you can set its identifier

to IDC_ADDRESS. If an edit box is used to enter an email address, you can change its

ID to IDC_EMAILADDRESS or IDC_EMAIL_ADDRESS. An identifier should have a

maximum of 30 characters. Notice that the ID contains C, which stands for Control.

If you plan to access an edit box in your code, you should create a variable for it. The

variable can be a CEdit or a CString object. The difference is that, if you want to access

the control as an MFC class, you should create the variable as a CEdit object. If you are

more interested with the value (as a string) of the control, you should declare the variable

as CString. Fortunately, you can add two variables for the same control.

Probably the most important characteristic of an edit control for both the programmer and

the user is the text it is displaying or that it can display. When you add an Edit control,

Visual C++ 6 displays Edit and Visual C++ 7 displays Sample edit box. This text is not

part of the control and does not show when the control comes up. It is only an indicator.