Technical Note #1
Title: The Zen of Hot Links Last Revised: 4/21/93
Description: The ins and outs of using Hot Links. How to define them for Excel. How to actually
find out the information that has changed and display it.
The purpose of a Hot Link is to allow you to monitor a very specific piece of data stored in the
files of another application. While this may sound similar to an OLE Client, there are significant
1. An OLE Client resides on a folder; a Hot Link is "Invisible".
2. An OLE Client only informs you of changes when you consciously click on Update Link; a Hot
Link informs you immediately if information changes.
3. An OLE Client allows you to see a whole chart or spreadsheet; a Hot Link is tied to a very
specific location on a spreadsheet or document.
Creating the Link
First, make sure you have the other application open. Then, open PackRat 5.0. From the Tools
Menu, choose Hot Links. Give the Link any name you'd like. For application, enter the name of
the executable file. DO NOT enter the whole path. The topic is the name of the document or
spreadsheet, including the path and extension.
Item deserves its own paragraph. This is where the most confusion is likely to set in. This is the
exact location that you want to monitor. The best example would be the cell in a spreadsheet
which contains the total you are monitoring. Now, you must enter this location in a very unique
way. Let's say we want to monitor the cell located at Row Eight, Column D of an Excel
spreadsheet. the notation for this location would be R8C4. In other words, R, Row number, C,
Column NUMBER. You MUST change the column letter to a number. This could lead to some
interesting calculations if you are looking at Column EJ (which would be C166). Sorry for the
inconvenience - it's one of those weird Windows things.
Next, assign a PackRat system variable in which to store the new value. Remember, SysVars
ARE case sensitive. You might want to write down the name of the SysVar for when you write
Macro is the name of the macro you want to run whenever the value changes. For now, choose a
pre-defined macro. Then, once you've seen the link in action, you can change it to one of your
Checking AutoConnect will mean that, every time you open PackRat, the link will be re-
established. Beneficial if it's a critical link, but it can slow down loading of the program.
If you didn't select AutoConnect, this would be a good time to connect the Link. After you do that,
go to the other app, and change the data that's being pointed to. If all went well, you will be
brought back to PackRat, and the macro you specified will be run. If it doesn't try recreating the
link, but first disconnect the existing one.
Displaying the Changed Value
Because a Hot Link stores its data in a SysVar, you cannot simply ask PackRatBASIC to display
the new value. You must first get that data from the SysVar into a local variable. This sample
macro shows an example of how this could be done:
Remember, the SysVar is case-sensitive, so enter it exactly as you did in the Hot Link.
Packrat 5.0 Technical Notes Page #: 2 Tech Note #1