Name
LineInput Function
Class
Microsoft.VisualBasic.FileSystem
Syntax
LineInput(filenumber
)
-
filenumber
(required; Integer) Any valid file number
Return Value
A String containing the line read from the file
Description
Assigns a single line from a sequential file opened in Input mode to a string variable
Rules at a Glance
Data is read into a buffer one character at a time until a line feed or carriage-return sequence (either
Chr(13)
orChr(13)+Chr(10)
) is encountered. When this happens, all the characters in the buffer are returned as a string, without the carriage-return sequence, and the buffer is cleared.After reading a line, the file pointer advances to the first character after the end of the line or to the end-of-file marker.
Example
The following code reads all of the lines in a text file and sends them to the Output window:
Dim fr As Integer = FreeFile( ) Dim sLine As String FileOpen(fr, "c:\data.txt", OpenMode.Input, OpenAccess.Read) Do While Not EOF(fr) Console.WriteLine(LineInput(fr)) Loop FileClose(fr)
Programming Tips and Gotchas
You use the LineInput function to read data from text files. To write data back to this type of file, use the PrintLine function.
VB.NET/VB 6 Differences
The VB.NET LineInput function corresponds
directly to the VB 6 LineInput
statement, with the
following differences:
The VB 6
LineInput
statement has a second argument,varname
, which is the variable to receive the line read by the function. It is not supported by the VB.NET LineInput function, since the ...
Get VB.NET Language in a Nutshell, Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.