Write CSV

Write CSV

Type: write-csv  ·  Package: CSV Activities v1.0.5  ·  Output: string

Writes a DataTable to a CSV file. Useful to export data in a format any system can import.

How it works

Dumps dataTable into the file at path using the given delimiter. By default it writes the column names as a header row (includeHeader = true). Returns the written path.

• Always overwrites: if the file exists, it is replaced. If the folder does not exist, it is created.
• Automatic quoting: a value containing the delimiter, double quotes or a line break is written in quotes ("Smith, Ann"), with inner quotes doubled.
• Values: each cell is converted to text with the machine’s regional settings (numbers with its decimal separator, dates with its format). To control the format, prepare text columns first (for example with ToString("yyyy-MM-dd")). Empty cells become empty fields.
• Lines: each row ends with a Windows line break (\r\n).
• Encoding: with utf-8 (default) the file gets the BOM, which helps Excel show accented characters correctly.

Required parameters

Parameter	Type	Default	Description
path	string	—	Path of the output CSV file, including its folder.
dataTable	DataTable	—	The table to write.

Optional parameters

Parameter	Type	Default	Description
delimiter	string	","	Field separator. Only the first character is used. For a tab, ((char)9).ToString().
includeHeader	bool	true	Write the header row with the column names.
encoding	string	"utf-8"	File encoding: utf-8, iso-8859-1, utf-16… See encoding.

Output

Returns a string with the path of the written file (as you gave it in path). A table with no rows produces a file with just the header (or an empty file with includeHeader = false).

Common errors

Message	Cause and fix
'dataTable' must be a DataTable.	The dataTable expression is not a table (null, a list or another type). Pass the variable holding the DataTable, for example the output of Read CSV or of a query.
The process cannot access the file '…' because it is being used by another process.	The destination file is open (for example in Excel). Close it before writing.
Access to the path '…' is denied.	No write permission on the folder.
Index was outside the bounds of the array.	delimiter is empty. Give a character.
'path' is required.	The path expression evaluated to null.

Example

Export a query result and email it:

DB Query    sql = "SELECT * FROM Customers"   → output: customers
Write CSV   path = "C:/export/customers.csv"   dataTable = customers   delimiter = ";"   → output: csvPath
SMTP Send   ...   subject = "Customer export"   attachments = arr(csvPath)

Related activities

• Read CSV — read a CSV.
• Write Excel Sheet — export to .xlsx.