More Data Grid Difficulties - Making it request data

[Trevor DeVore]

On Mar 16, 2010, at 8:10 AM, Len Morgan wrote:

> To answer your first question, the lines aren't getting colored and  
> I have a message that's supposed to print to the message box as it  
> goes by.  I went so far as to put a 500 ms delay in this routine (so  
> EVERY column would wait 1/2 a second just in case the message got  
> overwritten by a later message.

I think I need some more information about how you have set up your  
data grid. Where have you defined FillInData? Have you created a  
custom column behavior for your table as described in this lesson?

http://lessons.runrev.com/spaces/lessons/manuals/datagrid/lessons/7327-How-Do-I-Override-the-Default-Behavior-For-Rendering-Data-to-a-Cell-

> I'm not sure what you mean exactly by "what columns have you  
> defined".  They are all text fields, (e.g., no icons, images,  
> buttons, etc).  I create the data array by going though the returned  
> data a line at a time and creating a tab (col) delimited, cr (row)  
> delimited variable then use:

On the Columns tab of the data grid object inspector you define the  
columns in your data grid. This affects which columns appear in your  
data grid table.

> To clarify your first comment,  if I set the entire data array using  
> dgText, does it call FillInData for every line possible or only the  
> visible ones?

Only the visible ones. A data grid will only ask for data on an as- 
needed basis UNLESS you set the "cache controls" property to true. But  
that only works with forms so it won't apply in your case.

> The reason I ask is that one of the things I want to do with  
> FillInData is to get three more fields that don't come out of the  
> original query.  I have two dates that come out of another table and  
> have not been able to come up with any SQL query that would return  
> these fields in the original query.

In situations like this I have run the necessary queries, joined the  
results and then assigned the resulting data to the data grid.

>  What I want to do is when FillIndata gets to the first field (key  
> field), I can call another query for that one record only.  As each  
> row is processed, I can get these two dates.  This will not be a  
> processing burden IF I only fill the data that is on the screen at  
> the time.

If you want to go this route you could modify your FillInData routine  
to look something like this:

on FillInData pData
     ## Note: Not very efficient as FillInData is called for every  
column of every row
     ## Check if date column has been fill in yet.
     if GetDataOfIndex(the dgIndex of me, "Date 1") is empty then
         ## Query db and get date values...

         ## Assign to row in Data Grid
         SetDataOfIndex the dgIndex of me, "Date 1", theDateValue
     end if

     set the text of me to pData
end FillInData

> The last "field" I need isn't really a field but rather, based on  
> the value of this field, I need to set the row color.  This field I  
> DO have at the time theDataA array is created.

The instructions for colorizing a line described in the lesson should  
work then. Let me know about whether or not you set up the custom  
column behavior and we can go from there.

-- 
Trevor DeVore
Blue Mango Learning Systems
ScreenSteps: http://www.screensteps.com
Releasable Revolution Resources for Developers: http://revolution.bluemangolearning.com