Page 206 - DCAP408_WEB_PROGRAMMING

Windows Programming

Notes The new DDX_Text macro entry automates data transfer between the control identified by
IDC_CUSTOM_EDIT and your m_strCustomEditmember variable.
If you were to add a control map for the edit control, you'd see a CEdit member variable entry
added to the class definition, and a corresponding DDX_Control macro to map it to the control
ID. Consider this example:

DDX_Control(pDX, IDC_CUSTOM_EDIT, m_editCustom);
If you insert other variable types, you'll see different DDX_ macros used to map the various
types of controls to various data types. Table 12.1 lists some of these controls.

Table 12.1: Some Common Controls and Their Mapping Classes/Variables

Control Mapping Class Allowable Mapped Data Types
Static CStatic CString
Edit CEdit CString, DWORD, UINT, int, long
double, float, BOOL, short
COleDateTime & ColeCurrency
Button CButton None
CheckBox CButton BOOL
3-State CheckBox CButton int
Radio CButton int
ListBox CListBox CString, int
ComboBox CComboBox CString, int
Extended Combo CComboBoxEx CString, int
ScrollBar CScrollBar int
Spin CSpinButtonCtrl None
Progress Bar CProgressCtrl None
Slider Control CSliderCtrl int
List Control CListCtrl None
Tree Control CTreeCtrl None
Date Time Picker CDateTimeCtrl CTime, COleDateTime
Month Calendar CMonthCalCtrl CTime, COleDateTime

You can add some simple validation maps to certain controls, such as Edit controls. Depending
on the variable type mapped, the lower section of the Member Variables tab displays a section
that lets you specify validation information.

If you map a CString to an Edit control, for example, you can set the validation rules to limit the
maximum number of characters allowed in the Edit control. If you map an integer to the Edit
control, you can set upper and lower ranges for the entered value.

If you set any of these validation rules, ClassWizard adds DDV_ routines to the DoDataExchange()
function to perform validation, like this:
DDV_MaxChars(pDX, m_strCustomEdit, 10);

Several different DDV_ routines exist for the various types of validation rules, member variables,
and control types.

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