LineInput Function

Reads a single line from an open sequential file and assigns it to a String variable.

Public Function LineInput(ByVal FileNumber As Integer) As String

Parameters

• FileNumber
  Required. Any valid file number.

Exceptions

See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (You can compare the error number against the Number Property (Err Object).) However, when possible, you should consider replacing such error control with Structured Exception Handling Overview for Visual Basic.

Remarks

The LineInput function is provided for backward compatibility and may have an impact on performance. For non-legacy applications, the My.Computer.FileSystem object provides better performance. For more information, see File Access with Visual Basic.

Data read with LineInput is usually written to a file with Print.

Security Note:
When reading from files, do not make decisions about the contents of a file based on the file name extension. For example, a file named Form1.vb may not be a Visual Basic source file.

The LineInput function reads from a file one character at a time until it encounters a carriage return (Chr(13)) or carriage return/line feed (Chr(13) + Chr(10)) sequence. Carriage return/line feed sequences are skipped rather than appended to the character string.

Security Note:
Reading from a file with the LineInput function requires Read access from the FileIOPermissionAccess enumeration.

Example

This example uses the LineInput function to read a line from a sequential file and assign it to a variable. This example assumes that TestFile is a text file with a few lines of sample data.

Dim TextLine As String 
' Open file.
FileOpen(1, "TESTFILE", OpenMode.Input)
' Loop until end of file. 
While Not EOF(1)
   ' Read line into variable.
   TextLine = LineInput(1)
   ' Print to the console.
   WriteLine(1, TextLine)
End While
FileClose(1)

Smart Device Developer Notes

This function is not supported.

Requirements

Namespace: Microsoft.VisualBasic

**Module:**FileSystem

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

See Also

Tasks

How to: Write Text to Files with a StreamWriter in Visual Basic

How to: Write Text to Files in Visual Basic

Reference

Chr, ChrW Functions

Input Function

Other Resources

File Access with Visual Basic