Monday, April 20, 2020

Delphi Tip of the Day - Export to CSV

This weekend I had a bunch of data inside a FireDAC FDMemtable and I wanted to play around with that data in Excel. So, the first thing I did was review which data formats Excel would accept.

That's excellent! Excel allows both importing from XML and JSON both of which can done using FDMemtable.SaveToFile method. ( SaveToFile documentation )

I created an XML file using the SaveToFile method and then tried to import that file into Excel.

That didn't go so well. Where's my data? I'm starting to feel that "I hate Delphi" thing happening again! Let's try JSON. So. I created a JSON file using the SaveToFile method and then tried importing into Excel. 

"I just want the data in Excel."

That didn't go so well either. I've imported text files hundreds of times into Excel and it just worked. I wasn't in the mood to figure out what was going on. I'll save that for another day. I just want the data in Excel. 

"I know CSV works. Let's find a solution."

I know that text or csv files import just fine into Excel so let's see how to create a CSV file using Delphi. A quick google search turned up exactly what I was looking for, a simple solution written by Uwe Rabbe six years ago. Thank you Uwe!

This works with any TDataSet descendent! And just like that I love Delphi again.

Enjoy - Semper Fi
Gunny Mike

Feedback is always appreciated!

Wednesday, April 15, 2020

Delphi Tip of the Day - First Chance Exception

I'm in the process of upgrading a very old Delphi program that I wrote with my Turbo Pascal, top-down, structured-programming, mindset. One of the major updates I want is for the data to be in a database. So, I'm cruising right along making very good progress. After two days I finally get the algorithm working. And it's producing good results.

Now it's time to get those results into a database table. No big deal. FDMemtable and LocalSQL will do the trick. I'll just add a DataModule to the project. Drop in the necessary components. Add the fields using the fields editor.

I get everything working in the IDE. I'm good to go. All I need to do now is add the SQL. I code up the insert statements. I'm very excited. I will soon have the data in a database table. I push F9 and... BOOM!

"What the hell is a First chance exception?"

You've got to be kidding. I was so close. I started googling all over the internet trying to figure out what a First chance exception is. I just wanted an answer. After an hour or two I gave up. I was tired. I was frustrated. I'll deal with it in the morning. Off to bed I went.

"It turned out to be a very simple fix!"

The next day with a fresh attitude I returned to my project. It turns out this was a very simple fix. I didn't see or think about this the night before. When I added the DataModule to the project it was added to the bottom of the list.

The OnCreate method of Form1 calls the logic in another unit, which in-turn communicates with DataModule1. Because DataModule1 is created after Form1 gets created it caused an exception. All I had to do was move the DataModule1 before Form1.

I literally had the cart before the horse. I remember getting burned by this in the past but totally forgot about it.

Semper Fi,
Gunny Mike

Feedback is always appreciated.