The LA Fox Developer Newsletter

February 1998

Froms and Grids Revisited...

Yet Another Approach

to Forms and Grids

by Nick Neklioudov

[Ed. Note: Received this note/article in my e-mail box;

Here is the updated version of the article. Nick

So here is the revised article. Enjoy.]

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 Pasketton UT in January 1997.

This example contains a 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

ScroliBars = 2

Width = 400

Columnl.Width = 400

Columnl.Sparse = .F.

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

pageframe (or any other container you are using).

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

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

scrollbar 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 actua’ly

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

after that record pointer actually moves. If you want to move the

record pointer according to shown record, you may use

Grid.MouseDown and MouseUp events for that:

Grid.MouseDown

LPARAMETE~S nButton nShft, nXCoGrd, nyCoord

*

next two lines are here to prevent appearing

*

error messages 109 or 130

*

which Is happening If the focus inside a container

*

prevlousely was in the Editbox bound to Memo field.

thisform.anyControlOutsideGrid.SetFocus()

this.SetFocus()

Grid.MouseUp

LPARAMETERS nButton, nShift, nXCoord, nYCoord

thls.ActivateCell(1 ,1)

this.Columnl .cntMyContainer.myControl.SetFocus()

 

So, now 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”

However, that pageframe instance in the grid column has size

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

(Con’t, page 8)

Page 7