One of the most useful custom objects that I've ever written is my
master_detail object. It holds a prominent place in my toolkit. This article
will take you through the steps of how to write one and in the process
de-mystify the object.
First we want something that looks like Figure 1. Selecting a row in the top
DataWindow will display the details in the bottom. I'm sure that you've seen
this kind of DataWindow and you've probably written many of them. The key
here is not to tell you how to write this but how to simplify every one that
you will write in the future. For our example I will again use the example
database that came with PowerBuilder.
To build the control I first need to create a new custom object. I click on
File-New in the menu or just hit Ctrl-N and I get the dialog in Figure 1.
I've circled what you need to click on to make it easy for you.
Once y... (more)
This is the third and final part of a series presenting a proposal for the
use of the tag property of DataWindow columns. My original thought was to
provide a means to automatically set a microhelp for each column. Of course,
if you are using an MDI application you have a function to set the microhelp,
but that function is only available in MDI. If you are using any other
application type, then this is not available to you.
Even if you do have an MDI, I have found that the microhelp is not as useful
as I would like. The microhelp is always on the frame, nowhere near the
column. ... (more)
In my last article we explored what I call Advanced DataWindow Sorting. We
covered everything that we need for the DataWindow. In this article we are
going to polish what we did last month and make it look professional.
The main area of concern is our sort selector window as seen in Figure 1. It
does the job. It's just amateurish and doesn't provide the full flexibility
that we really need.
You may recall that the text of the sortable column is specified in the tag
property of the column in the DataWindow. (huh?)
We open the sort selector window with a parameter, something like t... (more)
Normally I try to write applications on the DataWindow or Appeon but every
now and then I get a question that makes me sit back and say, "Huh?"
In this case the question concerns the PostOpen event. I've seen that event
named different things: ue_post_open, postOpen, post_open, ue_postOpen, etc.
It has, as far as I can see, always had post and open in the name of the
event. Further, just about every framework that I've ever seen has had that
event in the base window.
The question that I was asked was, "Why is that event there?"
The programmer wanted to know why there was code in t... (more)
This article describes how to create a grid presentation window that allows
sorting by clicking on the column header.
To begin we need to create a grid DataWindow. I'm selecting just a few
columns from the employee table. Here is my sql for the DataWindow in Figure
Once we have created it I get the DataWindow painter shown in Figure 2.
There are several changes that we need to make. Let's change the status
column so it's no longer a set of radio buttons. This is a read-only screen
so let's remove the status and add a computed field.
To do this let's remove the Status column ... (more)