The LA Fox Developer Newsletter

January 1998

Yet Another Approach to

Forms and Grids

by Nick Neklioudov

[Ed. Note: Nick Neklioudov is a Fox (“all-kinds-of”) programmer

for last 11 years and lives in Halifax, Nova Scotia. As CNA,

Nick also provides network implementation and support, as well

as different kinds of computer consulting, support and trouble-

shooting tasks. He is currently working on contract basis.]

I believe all of us are familiar with that set of four navigational

buttons “First”, “Prior”, “Next”, “Last” we use for data entry or

maintenance forms. You need to put some code in their Click()

events, enable or disable navigation buttons, according to the

position of record pointer in a table. Of course, usually all we do

it only once, and save this commandgroup as a class for reuse.

I would like to suggest another approach for VFP 5.0 which

eliminates the need in that commandgroup at all.

Everybody knows, that we can put any control into a grid cell,

but maybe not everybody realizes that it is possible to put there

also any container, even the whole form, which gives us some

extra opportunities.

I created this sample after discussion about “Scrolling grid” in

the thread, started by Jon Paskett on UT this January.

This example contains pageframe, placed into a grid cell

instead of default textbox. The pageframe contains 3 pages with

all necessary controls and should be saved as class in a class

library.

Say, we use EMPLOYEE.DBF from Tasmanian Traders sample

as our data source. Our pageframe has Height = 300 and Width

= 400 , so we create a form, with a grid of 1 column, then drop

our new pageframe class into grid’s column, set CurrentControl

for the Columni to the pageframe and remove default textbox.

Also we have to make sure that grid properties are set to:

ColumnCount = I

DeleteMark= .F

GridLines = 0

HeaderHeight = 0.

Height 300

HighlightRow= .F.

RecordMark = .F.

RecordSource = “employee”

RowHeight = 300

ScrollBars = 2

Width = 400

Column 1 .Width = 400

Column 1 .Sparse = .F.

The trick is that now the grid cell has the exact size of the

pageframe.

After those settings we run our form and see the pageframe,

which has a vertical scrollbar on the right side. We can use this

scroilbar to navigate through our data source like we do it with a

text in MS Word. Note, that the record shown in the pageframe

is not the current record in our data source until we actually

click anywhere on the pageframe or any of its controls. Only

after that record pointer actually moves.

So, in this case we have no need in any code we previously

used in our navigational commandgroup.

This approach “as is” may be used for forms, which works

directly with tables or views, and use APPEND BLANK for

adding records, or, for any forms which are used just to repre-

sent data.

Sometimes, when you open this form in Form Designer again,

after adding pageframe to the grid, it can give you an error

message “Error loading file record number X - Pageframel (or

one of its members). : Pageframe cannot be sized that small”,

despite of the fact, that pageframe instance in the grid column

has size 300 x 400 pixels. I opened my form’s .SCX file by USE

MYFORM.SCX and found, that by unknown reasons there are

no Width and Height properties defined in Properties field for the

record containing information about the pageframe. It never

happened, when I was experimenting in VFP 3.0. To fix that, it

is enough just to add to Property field manually:

Height = 300

Width = 400

By the way, I would not recommend this kind of grid for VFP

3.0, because it seems to work differently there, and give strange

visual effects, but for VFP 5.0, it works just fine, as far as I

tested it. I would be glad to get any feedback about any prob-

lems regarding this approach.

(Nick can be reached atad587@chebucto.ns.ca.]

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