HMG: Grid versus Browse [Updated 25th March 2009]

CCH :
According to the MiniGUI Help File, a Browse control is a general purpose database browser.
while a control Grid is a container object that displays data in rows and columns, and is similar in appearance to a Browse window.

Q1. So, what are the differences ?

Q2. When to use BROWSE ?

Q3. When to use GRID ?

Sudip :

Q4. For browse control (for data editing), do we need to use table "EXCLUSIVELY" ?


Answers

1. Rathinagiri (HMG Forum) :

1.1 Browse controls are always linked with one table (that too a .dbf table).

1.2 Grid controls are for used for other purposes where, you wish to represent data in row,col format. For example, it may show a two dimensional array!

1.3 All the browse controls are grid controls but not vice versa.

2. MOL aka Malek, Poland (HMG Forum)

2.1 I think you will have problems with browsing huge tables (exhausting memory, etc) while using grid. Using Browse, I didn't found problems with database which has 100MB.

2.2 You need to open table in exclusive mode only when you want to add records or edit record via ALT-A, ALT-E.

2.3 If you open table in shared mode, you must write your own function to add, edit or delete rows.

2.4 WORKAREA property of Browse is available at control definition only.


3. Sudip, Kolkata, West Bengal India

3. 1 I just found a big difference in Grid and Browse in MiniGUI extended!
If you use SET AUTOADJUST ON. Then Grid will be auto adjusted, but normal Browse (not tsbrowse) will not! :)

3.2 As per help file (hmg_hlp.chm), we can set WORKAREA during definition of browse only! Cannot change on the fly!

3. Bicahi Esgici, HMG Forum, Turkey

Hi to all Clipper and especially HMG fans

I want give a humble answer to an unanswered question in Saturday, March 21, 2009 post HMG; Grid versus Browse;

Sudip ;

Q4. For browse control (for data editing), do we need to use table "EXCLUSIVELY" ?

A4. No. If your application will run in a single machine this doesn’t matter. In a network environment you can’t open your files exclusively. If so, only one user (who come first) can use your application. Than, you MUST use SHARED mode. BTW you don’t need specify SHARED mode option every open (USE); setting globally EXCLUSIVE OFF is sufficient.

When a file open by shared, editing need some considerations. Under Browse or not, you have LOCK every record before and UNLOCK after edit ( changing record pointer also issue an UNLOCK). LOCK ( .T.) property of BROWSE successfully achieve this duty for you.

While a BROWSE active, ALT-A allow row appending to table. This is only issued an APPEND BLANK command. This command automatically LOCK new appended (empty) record. So, doesn’t require any precaution.

Precaution required for operations intended multiple records, such as PACK, ZAP, APPEND FROM, DELETE FOR ... / ALL, RECALL FOR ... / ALL, REPLACE FOR ... / ALL, UPDATE ON ...

The best way for such operations is "close" application to network ( all user ) and performing on a single machine. Another way is using FLOCK() for a limited time.

I hope that this answer will be useful.

Regards and happy HMG’ing

Programming MDI with MiniGUI - Part II [Updated 22nd march 2009]

After tinkering with MDI programming and with the help of Grigory of HMG Extended Forum :-






Basic syntax for a Browse which works perfectly in a non-MDI environment is as follows :-

[ @ , ] BROWSE
[ ID ]
[ OF | PARENT | DIALOG ]
WIDTH
HEIGHT
HEADERS
WIDTHS
WORKAREA
FIELDS
[ VALUE ]
[ FONT SIZE ]
[ BOLD ] [ ITALIC ] [ UNDERLINE ] [ STRIKEOUT ]
[ TOOLTIP ]
[ BACKCOLOR ]
[ DYNAMICBACKCOLOR ]
[ DYNAMICFORECOLOR ]
[ FONTCOLOR ]
[ ON GOTFOCUS | ]
[ ON CHANGE | ]
[ ON LOSTFOCUS | ]
[ [ ON DBLCLICK | ] | [ EDIT | ALLOWEDIT [ INPLACE ] ] [ APPEND | ALLOWAPPEND] ]
[ ON HEADCLICK | ]
[ WHEN ]
[ VALID ]
[ VALIDMESSAGES ]
[ READONLY ]
[ LOCK ]
[ DELETE ]
[ NOLINES ]
[ IMAGE ]
[ JUSTIFY ]
[ NOVSCROLL ]
[ HELPID ]
[ BREAK ]

However, please note that for MDI environment:-

[ [ ON DBLCLICK | ] | [ EDIT | ALLOWEDIT [ INPLACE ] ] [ APPEND | ALLOWAPPEND] ]

a) EDIT/APPEND does not work
b) You may use EDIT INPLACE

This is exactly why I wrote my own UDF to replace them :-)

Update on 23rd March 2009

Finally, perfected (with the help of Grigory of HarbourMiniGUI Forum) TILING/CASCADE of Child Windows populated with different DBF

MDI Programming with MiniGui [Updated 12th March 2009]

Having pushed the very stable HMG to it's limits and as documented in my previous articles, I was encouraged by Sudip and decided to take a serious look at HMG Extended ie MiniGui as most of the apps that I have in mind must be MDI in nature..

This is what I started With


What did I do Next ?

I took the codes from FAS4HMG and copied the Project folder under the MiniGui folder. I was then able to recompile it as a MIDI apps with some minor adjustments.

Code Snippet
DEFINE WINDOW MainForm ;
AT 0,0 ;
WIDTH 600 ;
HEIGHT 480 ;
TITLE 'FAS4MiniGUI' ;
MAIN ;
MDI
DEFINE MAIN MENUEX

Opening First Child Window, containing a BROWSE


Opening two Child Windows & CASCADE


Tiling Vertically

Code Snippet
TILE MDICHILDS VERTICAL

Tiling Horizontally

Code Snippet
TILE MDICHILDS HORIZONTAL

More to come ...

HMG : How to Create Browses, the easy way ? (Updated 9th March 2009)

In FAS4DOS/FAS4XHB and FAS4HMG, I was using DBEDIT() as the primary data entry mechanism for user input.


On studying the numerous samples in HMG, I decided to replace all the text DBEDIT() with HMG's BROWSE. The following was achieved by using BROWSE functionality in place of DBEDIT() within FAS4HMG



How did I achieve this ?

Code Snippet

DEFINE WINDOW BrowseGLACForm ;
AT 0,0 ;
WIDTH 640 HEIGHT 480 ;
TITLE 'Browse Chart of Accounts' ;
CHILD ;
NOMAXIMIZE;
ON INIT OpenTables() ;
ON RELEASE CloseTables()


DEFINE STATUSBAR
DATE
STATUSITEM ' / Double Click To Edit' WIDTH 190
STATUSITEM 'Alt+A: Append Record' WIDTH 140
STATUSITEM ': Delete Record' WIDTH 140
CLOCK
END STATUSBAR

@ 10,10 BROWSE Browse_1 ;
WIDTH 580 ;
HEIGHT 400 ;
HEADERS { 'GL Code' , 'GL Name' , 'GL Type', 'GL Group'} ;
WIDTHS { 80 , 320 , 80 , 80 , 120 } ;
WORKAREA GLAC ;
FIELDS { 'GLAC->GLCODE' , 'GLAC->GLNAME' , 'GLAC->GLTYPE' , 'GLAC->GLGROUP'} ;
VALUE 1 ;
EDIT ;
APPEND;
DELETE;
LOCK

END WINDOW

CENTER WINDOW BrowseGLACForm

BrowseGLACForm.Browse_1.SetFocus

ACTIVATE WINDOW BrowseGLACForm

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