Richard (Rik) Brooks

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Top Stories by Richard (Rik) Brooks

Have you ever used a datastore that ran without a problem while you were developing your application, but once you've compiled it stopped running? Let me tell you that's a difficult bug to fix. I remember it so well. I kept going back and forth. How in the world could the DataWindow work at design time yet not in the executable? I remember that I checked the return value of the datastore. I finally noticed that the datastore returned a -1. That's such a strange thing. The datastore returns the number of rows that were returned or a -1. The help files used to say that a -1 was in case of 'an error'. It goes into a lot more detail in version 12.5 but still falls somewhat short of giving you the whole answer. Here it is... If you set the dataobject property of a DataWindow or datastore object, then at runtime PowerBuilder will be unable to find it. You will get a retu... (more)

Extending SQLCA

We are going to create a bare-bones email object. Of course you can expand that in the future if you like, but for now, let's just create the functionality that we need. I start by creating a custom class. In case you aren't familiar with the process look at Figure 1. Let's start with an instance variable. N_cst_mailer Instance Variables private mailMessage io_mail_message // The message to send I made the instance variables private so let's write a couple of functions to populate our mail Message. We'll start with the TO. Note that the io_mail_message contains an array of objec... (more)

Using the Tag Property – Part 3

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)

The PostOpen Event – Why It Is So Important

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)

DataWindow Sorting with Column Headers

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 1. 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)