Skip to main content

ListView - Sorting by Number or Date

A lot of people are faced with the challenge of sorting a ListView list by numeric value or date. If you do a search, you'll see all kinds of API re-writes and special functions to make it work.

Of course, DotNet has its own way of doing it which looks equally troubling.

The easiest workaround is simply to change your date format to be YMD but that isn't typically a good solution for US companies or applications that show the long date.

But there's an easier way. It was briefly noted here but I wanted to give VFP developers a very straightfoward example.

Short Answer: Create a new column on the list view with a width of zero. Populate the list with the DTOS or sortable version of the value and then instead of setting the SortKey to the displayed column - set it to the OTHER column instead.

This works like a charm.

Some code (if you will)

In the ColumnClick method of the ListView, put in
LPARAMETER columnheader
IF columnheader.Text = "Date"
THIS.SortKey = columnheader.Index
ELSE
THIS.SortKey = columnheader.index-1
ENDIF

WITH THISFORM.ListView
.ColumnHeaders.Add(,,"FileName",100)
.ColumnHeaders.Add(,,"Date",60)
.ColumnHeaders.Add(,,"RealDate",0)

lo = .ListItems.Add(,"NewFile","New File")
lo.SubItems(1) = DTOC(DATE())
lo.SubItems(2) = DTOS(DATE())
lo = .ListItems.Add(,"OlderFile","Old File")
lo.SubItems(1) = DTOC(GOMONTH(DATE(),-5))
lo.SubItems(2) = DTOS(GOMONTH(DATE(),-5))

lo = .ListItems.Add(,"ROlderFile","Really Old File")
lo.SubItems(1) = DTOC(GOMONTH(DATE(),-12))
lo.SubItems(2) = DTOS(GOMONTH(DATE(),-12))
.View = 3
.Sorted = .T.
ENDWITH

Now a few things to note:
1. ListViews can only show TEXT in their columns. That's why I'm using DTOC which makes it appear in the standard format but then DTOS to put it into a useful SORTABLE format

2. The ColumnClick method shown here is really basic. If you wanted to add support for ascending and descending orders, it might look like this:

Procedure ColumnClick
LPARAMETERS ColumnHeader

IF THIS.sortOrder = 0
THIS.SortOrder = 1 && Descending
ELSE
THIS.SortOrder = 0 && Ascending
ENDIF
IF columnHeader.Text = "Date"
THIS.SortKey = ColumnHeader.Index
ELSE
THIS.SortKey = ColumnHeader.Index - 1
ENDIF

Now if you need to do this for a number, instead of using DTOC and DTOS , just pad the numbers with zeroes.

Comments

Post a Comment

Popular posts from this blog

Elevating Project Specifications with Three Insightful ChatGPT Prompts

For developers and testers, ChatGPT, the freely accessible tool from OpenAI, is game-changing. If you want to learn a new programming language, ask for samples or have it convert your existing code. This can be done in Visual Studio Code (using GitHub CoPilot) or directly in the ChatGPT app or web site.  If you’re a tester, ChatGPT can write a test spec or actual test code (if you use Jest or Cypress) based on existing code, copied and pasted into the input area. But ChatGPT can be of huge value for analysts (whether system or business) who need to validate their needs. There’s often a disconnect between developers and analysts. Analysts complain that developers don’t build what they asked for or ask too many questions. Developers complain that analysts haven’t thought of obvious things. In these situations, ChatGPT can be a great intermediary. At its worst, it forces you to think about and then discount obvious issues. At best, it clarifies the needs into documented requirements. ...
Post a Comment
Read more

Respect

Respect is something humans give to each other through personal connection. It’s the bond that forms when we recognize something—or someone—as significant, relatable, or worthy of care. This connection doesn’t have to be limited to people. There was an  article  recently that described the differing attitudes towards AI tools such as ChatGPT and Google Gemini (formerly Bard). Some people treat them like a standard search while others form a sort of personal relationship — being courteous, saying “please” and “thank you”. Occasionally, people share extra details unrelated to their question, like, ‘I’m going to a wedding. What flower goes well with a tuxedo?’ Does an AI “care” how you respond to it? Of course not — it reflects the patterns it’s trained on. Yet our interaction shapes how these tools evolve, and that influence is something we should take seriously. Most of us have all expressed frustration when an AI “hallucinates”. Real or not, the larger issue is that we have hi...
Post a Comment
Read more

Friend vs Therapist vs LLM: Shades of Grey

The conversations with AI series brings up a single point and then compares it between different LLM engines. These types of conversations were one of the many contributing factors to my writing of " Towards Consciousness " that explores the benefits and issues of creating a conscious AI. In this scenario, I was interested in seeing how an LLM might differ from a friend or therapist on issues that may have nuanced responses or contexts. In doing so, I came up with an interesting discussion on shades of grey. My Premise: Is it a bit strange to be using an LLM as a sober second thought? Every time I walk down this path of “why use an LLM to do certain things”, I come back to the alternatives that people like to say. “Why not bring it up with a friend?” A friend typically has your back or will say whatever to support their own agenda. “A therapist?” That’s someone who is “trained” to be impartial. But a computer? A computer is impartial based on two logical outcomes. If you say ...
Post a Comment
Read more