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DIAOLOG BOXES AND

CONTROLS

M.SUSHMERA

Lecturer in IT Department

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Dialog box

It is a temporary window created by anapplication to retrieve user input.

A dialog box contains one or more childwindow controls with which the user canenter text, choose options or direct theaction of the command

The advantage of using dialog box is thatit can be constructed easily using a dialogbox editor program.

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TYPES OF DIALOG BOXES

The two kinds of dialogs are modal and modeless.

The CDialog base class supports both modal and modeless dialogs

Modal Dialog Box:

The user cannot work elsewhere in the same application (more correctly, in thesame user interface thread) until the dialog is closed. Example: Open File dialog

Modeless Dialog

The user can work in another window in the application while the dialog remainson the screen

Example: Microsoft Word's Find and Replace dialog is a good example of a

modeless dialog; you can edit your document while the dialog is open.

Controls.

A dialog contains a number of elements called controls. Dialog controls include editcontrols, buttons, list boxes, combo boxes, static text, tree views, progressindicators, sliders, and so forth.

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CREATING A DIALOG BOX

Design a dialog box using the dialog box editor. All theprograms resources are saved in a single rc file.

Each child window control within the dialog box is givenan ID number.

Each dialog box requires a message passing function tobe added to the program.

The program activates the dialog box by calling theDialogbox function, passing the dialog box name and thedialog box function address or parameters.

The dialog box stays on the screen until the EndDialogfunction is called from within the dialog box function. Thiscloses the dialog box and returns control to the windowthat called the dialog box.

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Creation and Initializing Dialog

Box Use either one of these constructors to construct a resource-

based modal dialog box. One form of the constructor providesaccess to the dialog resource by template name. The otherconstructor provides access by template ID number, usuallywith an IDD_ prefix (for example, IDD_DIALOG1).

1.CDialog( LPCTSTR lpszTemplateName, CWnd*pParentWnd = NULL );

2. CDialog( UINT nIDTemplate, CWnd* pParentWnd =NULL );

3. CDialog( );

Initialisation1. virtual BOOL OnInitDialog( );

2. virtual int DoModal( ) Call this member function to invoke the modaldialog box and return the dialog-box result when the done.

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CONTROL MFC Class

Push button,check

box,radio button

CButton

Edit Control CEditBox

ListBox CListBox

ComboBox CComboBox

TreeControl CTreeCtrl

ScrollBar CScrollBar

Static text,outline of a

rectangle

CStatic

CONTROLS IN DIALOG BOX

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Retrieving data from the dialog object

1. GetDlgItem( int nID, HWND* phWnd ) ;nID Specifies the identifier of the control or child

window to be retrieved.

phWnd A pointer to a child window.

2. int GetDlgItemText( int nID, LPTSTR lpStr, int

nMaxCount ) ;nID Specifies the integer identifier of the control

whose title is to be retrieved.

lpStr Points to the buffer to receive the controls title or text.

nMaxCount Specifies the maximum length (in bytes) of the

string to be copied to lpStr. If the string is longer thannMaxCount, it is truncated.

3. void SetDlgItemText( int nID, LPCTSTR lpszString );

nID Identifies the control whose text is to be set.

lpszString Points to a CString object or null-terminated stringthat contains the text to be copied to the control.

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CONTROL CLASSES-CButton Class

1. CButton ClassBOOL OnInitDialog()

{

CButton *OK,*CANCEL;

OK=(CButton *)GetDlgItem(IDOK);

CANCEL=(CButton *)GetDlgItem(CANCEL);

OK->EnableWindow(FALSE);

Return TRUE;

}

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2. CEditBox Class

The CEdit class provides the functionality of a Windows editcontrol. An edit control is a rectangular child window in whichthe user can enter text.

Message-map entries and a description of the cases in which theywould be sent to the parent:

ON_EN_KILLFOCUS The edit control loses the input/keyboardfocus.

ON_EN_SETFOCUS Sent when an edit control receives the inputfocus.

ON_EN_UPDATE The edit control is about to display altered text.Sent after the control has formatted the text but before it screens thetext so that the window size can be altered, if necessary.

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3. CListBox Class

The CListBox class provides the functionality of a Windowslist box. A list box displays a list of items, such as filenames,that the user can view and select.

In a single-selection list box, the user can select only one item.In a multiple-selection list box, a range of items can be

selected. When the user selects an item, it is highlighted andthe list box sends a notification message to the parent window.

FUNCTIONS

GetText(LPSTR) ---to get the text given in the edit box

SetText(LPSTR)-- to get the text given in the edit box

SetFocus-focus the cursor to the particular control.

int AddString(LPSTR)-calls the member function to addastring to a list box.

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4.ScrollBar Scroll bar is a rectangle that contains a scroll box and has direction arrows at both ends. Scroll

bar sends a notification message to its parents whenever the user clicks the mouse in thecontrol.

void GetScrollRange( LPINT lpMinPos, LPINT lpMaxPos ) const;

lpMinPos Points to the integer variable that is to receive the minimum position.

lpMaxPos Points to the integer variable that is to receive the maximum position.

void SetScrollRange( int nMinPos, int nMaxPos, BOOL bRedraw = TRUE );

Call this member function to set minimum and maximum position values for the givenscroll bar. Set nMinPos and nMaxPos to 0 to hide standard scroll bars.

int GetScrollPos( int nBar ) const;

Specifies the current position of the scroll box in the scroll bar if successful; otherwise 0.

nBar Specifies the scroll bar to examine. The parameter can take one of the followingvalues:

SB_HORZ Retrieves the position of the horizontal scroll bar.

SB_VERT Retrieves the position of the vertical scroll bar.

BOOL OnInitDialog()

{ CScrollBar *sb;

sb=(CScrollBar *)GetDlgItem(IDC_SCROLLBAR1);

sb->SetScrollRange(1,100,TRUE);

sb->SetScrollPos(1,TRUE);

Return TRUE;

}

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5. Tree Control

This control is a window that display the hierarchicalList of items such as the heading in and document

and the entries in an index or the files and directorieson the text. Each item consists of a label and anoptional bitmap. Each item can have associated subitem bit, by clicking the item, the user can expand theassociated list of items.

To manipulate with the tree control, MFC hasprovided a class called CTreeCtrl.

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CTreeCtrl Control

FUNCTIONS

HTREEITEM InsertItem( LPCTSTR lpszItem, HTREEITEMhParent = TVI_ROOT, HTREEITEM hInsertAfter =

TVI_LAST );lpszItem Address of a string containing the items text.

hParent ->Handle of the inserted items parent.

hInsertAfter -> Handle of the item after which the new itemis to be inserted.

BOOL DeleteItem(HTREEITEM)the provided handle toremove.

BOOL DeleteAllItem()all items in the tree control will beremoved.

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THANK YOU