<DiskFile variable>.ReadLine (Function)

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Handling errors
Position in the file
Managing the ANSI/UNICODE format

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<DiskFile variable>.ReadLine (Function)

In french: <Variable FichierDisque>.LitLigne

Reads a line in an external file.

Example

// Open an external file
MyTextFile is DiskFile
ResRead is string
IF MyTextFile.Open("C:\MyDirectories\File.txt", foReadWrite) = True THEN
// Read a line in this file
ResRead = MyTextFile.ReadLine()
...
END

Syntax

Reading a file line by line Hide the details

<Result> = <File used>.ReadLine([<Separator>])

<Result>: Character string or UNICODE character string

Line read in an external file.
EOT constant if the end of file has been reached.
Empty string ("") if an error occurred. In this case, the ErrorOccurred variable is set to True.
Remark: A line ends with a CR character (Carriage Return).

<File used>: DiskFile variable

Name of the DiskFile variable initialized with fOpen or fCreate.

<Separator>: Character string

Separator used between the lines. The default separator is the Carriage Return (CR).

New in version 2024

Reading a file line by line using a procedure Hide the details

<Result> = fReadLine(<File used> , <WLanguage procedure> [, <Separator>])

<Result>: Integer

Number of lines read.
Remark: A line ends with a CR character (Carriage Return).

<File used>: Integer or DiskFile variable

Name of the DiskFile variable initialized with fOpen or fCreate.

<WLanguage procedure>: Procedure name

Name of the WLanguage procedure ("callback") called for each line read in the file. This procedure is used to manipulate the current line. For more details on this procedure, see Parameters of the procedure used by fReadLine.

<Separator>: Character string

Separator used between the lines. The default separator is the Carriage Return (CR).

Remarks

Handling errors

<DiskFile variable>.ReadLine throws an error in the following cases:

the file is not opened,
the file is not accessible in read mode,
the file is locked by another computer or by another application. <DiskFile variable>.Unlock is used to unlock an external file.

Position in the file

When opening a file, the current position corresponds to:

the first file byte (by default),
the last byte of the file is the file is opened in "addition" mode (foAdd constant).

This position can be modified by <DiskFile variable>.Seek.

<DiskFile variable>.ReadLine reads the specified elements from the current position. Once <DiskFile variable>.ReadLine has been executed, the current position is set to the last byte read. <DiskFile variable>.ReadLine returns the EOT constant if the end of the file has been reached.

Managing the ANSI/UNICODE format

The <DiskFile variable>.ReadLine function reads:

a Unicode string in a Unicode file.
an Ansi string in an Ansi file.

The file is created or opened with fCreate/fOpen by specifying the file type.

Depending on the format of the external file used, some conversions are required once a character string was read in an external file:


	Current computer	External file in ANSI format (fOpen or fCreate associated with the foAnsi constant)	External file in UNICODE format (fOpen or fCreate associated with the foUnicode constant)
<DiskFile variable>.ReadLine function	PC running Windows	Read operation in ANSI format Conversion to UNICODE possible with <String type>.AnsiToUnicode
	Mobile	Read operation in UNICODE format Conversion to ANSI possible with UnicodeToAnsi

Remark: If the result of <DiskFile variable>.ReadLine of an ANSI file is assigned to a UNICODE string (and vice versa), the conversion will be implicitly performed.

For more details, see Managing UNICODE

Business / UI classification: Business Logic

Component: wd290std.dll