Q: Writing CSV to variable location - csv

Question

Very new to AppleScript and have looked for solutions elsewhere unsuccessfully, apologies if I simply missed the answer elsewhere. Thanks for any help.
Background: I am using AppleScript to prompt the user for a directory, then create numerous folders in that directory with other prompts. As prompts are answered, I want to create a CSV that records these answers to prevent repeated answers and also allow the user to terminate the script and return later without losing items stored in lists. CSV seems the simplest way to do this.
Question- if I target the CSV to a static path I can successfully create the CSV and record to it. If I create a path from a prompt I receive the error: Finder got an error: Can’t make alias "Macintosh HD:Users:MyAccount:_Sample_Directory:" into type constant. number -1700 from alias "Macintosh HD:Users:MyAccount:_Sample_Directory:" to constant
What am I missing?
FYI- using this as basis for the WriteTo function.
Sample Script:
set MyList to {"A", "B", "C"}
tell application "Finder"
--This Works, but doesn't nest in the variable folder--
--set CSVFile to (path to desktop as text) & "List.csv"
--This is the goal:dynamic directory--
set ParentFolder to (choose folder with prompt "Select Folder")
set CSVFile to (path to ParentFolder as string & "List.csv") as POSIX file as alias
end tell
set TheResult to writeto(CSVFile, MyList, list, true)
on writeto(targetFile, theData, dataType, apendData)
try
set openFile to open for access file targetFile with write permission
if apendData is false then set eof of openFile to 0
write theData to openFile starting at eof as dataType
close access openFile
return true
on error
try
close access file targetFile
end try
return false
end try
end writeto

Answer 1

In your script, you do not need to tell application "Finder". So you can remove the tell / end tell.
The error in your script comes from line:
set CSVFile to (path to ParentFolder as string & "List.csv") as POSIX file as alias
Your sub-routine writeto accepts the targetfile to be in form of string like :
"disk:Users:me:folder:list.csv.
Therefore your first line could be reduced to :
set CSVFile to (ParentFolder as string) & "List.csv"
Yes, you can write your data in csv. But I am not sure it is the best choice. When you write the list {"A","B","C"} in your file, you are not writing text. So Applescript does a conversion from list to text. In this example the result is "listutxtAutxtButxtC". It depends what you want to do with that file, but to make it readable, it is better to write text in text file. You can do this by looping through all items of MyList to write each one as a text:
repeat with x in MyList
set TheResult to writeto(CSVFile, x, list, true)
end repeat
In above example, I still use datatype = list, instead of text. It does not matter because the subroutine does not use that parameter.I guess this is for future use.
Still it may not give you the result you're looking for. The text in file will be "ABC". To avoid this, I suggest you to add a return (or a tab) for each data you write in the file. Do to so, change the line in the writeto sub-routine :
write (theData & return) to openFile starting at eof as dataType
Then your cvs file will be
A
B
C
Which is easy to read.