Let us show you a few tips with the Xojo development, which we found to be helpful in the last weeks:
The CType() function allows you to convert a value to a different type and we found it helpful to convert from boolean to integers. We use it here to shrink our code for counting how many boolean variables are set. Please read this snippet:
This is for matching a new order to existing customer database. The new order may have the same name, email, phone and we look for best match in existing table. For this we match the values and set these boolean variables. Then we count points on how many are set. For the email match we count three points as a special case. This usually finds us the right customer in a lot of cases, even if they changed name, email, company name or phone, but keep one or two values equal.
But now use CType() to directly convert boolean to integer and add the boolean. When converted to integer, a true value becomes 1 and false becomes 0. For email we add 3 if set and 0 if not set. And all can be nicely formatted using underscore character to continue the line:
The new code is shorter, hopefully easier to read and performs better. What do you think?
Local variable to cache
I have been using this technique a lot to speed up code here: We define a local variable with the same name as a global function, property or otherwise expensive thing to get. A few examples:
In a web application:Dim session As session = session
In any project type:Dim app As app = app
In a Desktop project with a ListBox control named List:Dim List As ListBox = Self.List
Or in a Web project with a listbox:Dim List As WebListBox = Self.List
For a window the same:Dim MainWindow As MainWindow = MainWindow
Because in all cases you call a function, which is relative expensive compared to a local variable. App is a function, which looks up the current app object (via REALbasic._GetAppObject function). Session is a global function, which lookup the current thread and returns the associated session object (via _WebSupport.Session function). For a control on a webpage and window, you get a call to a function to lookup the control by name (via DesktopWindow._ControlByName function). Same for global window references (using REALbasic._GetImplicitDesktopWindow).
You find feature requests in the Xojo issues database for improving all this cases on the framework/compiler side.
e.g. #71958 Make App faster by making App a global property for all targets
To implement this feature, you may just go through your code and search for e.g. "List." When you see a method with a lot of positions found in the code, you enter the method and paste this line on the top of the method:Dim List As ListBox = Self.List
This way you can quickly find spots where this is worth it.
Remember position in Listbox
For a lot of list boxes in the user interface, we would like to remember the current selection and scroll position. The easiest version would be to stay at about the same position. So before updating the listbox, you query ListIndex and ScrollPosition:
If you like to do better, not just remember the list index, but the current selected RowTag with the database row ID, so you can on restore select the same record, even if it moved.
Add CancelClose events for work windows
For a lot of automations we have a window, which shows progress and has some controls to start, stop, pause or continue a batch processing. For these window we recommend to add a CancelClose event like this:
This avoids accidentally closing the window before the job is done.
Scale text in PaintCellText for Listbox
We sometimes use bigger row sizes to show multi line text like addresses. These addressees may have text wider than the current column and higher than the current row. We have this handy code to scale down font size until it fits:
Of course we use that only for columns, that need the scaling and not for all column. And as you see we define constants in the window to keep track of which column number is for which value.
Thanks for reading and if you have more tips to share yourself, please post to the Xojo forum or on your own blog.