FileSystemProxy.ReadAllText Method

Definition

Namespace:

Microsoft.VisualBasic.MyServices

Assembly:

Microsoft.VisualBasic.Forms.dll

Returns the contents of a text file as a String.

Overloads

ReadAllText(String)	Returns the contents of a text file as a String.
ReadAllText(String, Encoding)	Returns the contents of a text file as a String.

ReadAllText(String)

Returns the contents of a text file as a String.

public:
 System::String ^ ReadAllText(System::String ^ file);

public string ReadAllText (string file);

member this.ReadAllText : string -> string

Public Function ReadAllText (file As String) As String

Parameters

file

String

Name and path of the file to read.

Returns

String

String containing the contents of the file.

Exceptions

ArgumentException

The path is not valid for one of the following reasons: it is a zero-length string; it contains only white space; it contains invalid characters; or it is a device path (starts with \\.\); it ends with a trailing slash.

ArgumentNullException

file is Nothing.

FileNotFoundException

The file does not exist.

IOException

The file is in use by another process, or an I/O error occurs.

PathTooLongException

The path exceeds the system-defined maximum length.

NotSupportedException

A file or directory name in the path contains a colon (:) or is in an invalid format.

OutOfMemoryException

There is not enough memory to write the string to buffer.

SecurityException

The user lacks necessary permissions to view the path.

Examples

This example reads the contents of Test.txt into a string and then displays it in a message box.

Dim reader = My.Computer.FileSystem.ReadAllText("C:\test.txt")
MsgBox(reader)

This example reads the contents of the ASCII file Test.txt into a string and then displays it in a message box.

Dim reader = My.Computer.FileSystem.ReadAllText("C:\test.txt",
   System.Text.Encoding.ASCII)
MsgBox(reader)

Remarks

The ReadAllText method of the My.Computer.FileSystem object allows you to read from a text file. The contents of the file are returned as a string.

The file encoding can be specified if the contents of the file are in an encoding such as ASCII or UTF-8. If you are reading from a file with extended characters, you need to specify the file encoding using another overload of the ReadAllText method.

Do not make decisions about the contents of the file based on the name of the file. For example, the file Form1.vb may not be a Visual Basic source file. Verify all inputs before using the data in your application.

The following table lists examples of tasks involving the My.Computer.FileSystem.ReadAllText method.

To	See
Read from a text file	How to: Read from Text Files

See also

• Encoding
• ReadAllText(String)
• StreamReader(Stream, Encoding)
• Objects (Visual Basic)
• Reading from Files in Visual Basic
• How to: Read Text from Files with a StreamReader (Visual Basic)
• Troubleshooting: Reading from and Writing to Text Files
• Walkthrough: Manipulating Files and Directories in Visual Basic
• File Encodings

ReadAllText(String, Encoding)

Returns the contents of a text file as a String.

public:
 System::String ^ ReadAllText(System::String ^ file, System::Text::Encoding ^ encoding);

public string ReadAllText (string file, System.Text.Encoding encoding);

member this.ReadAllText : string * System.Text.Encoding -> string

Public Function ReadAllText (file As String, encoding As Encoding) As String

Parameters

file

String

Name and path of the file to read.

encoding

Encoding

Character encoding to use in reading the file. Default is UTF-8.

Returns

String

String containing the contents of the file.

Exceptions

ArgumentException

The path is not valid for one of the following reasons: it is a zero-length string; it contains only white space; it contains invalid characters; or it is a device path (starts with \\.\); it ends with a trailing slash.

ArgumentNullException

file is Nothing.

FileNotFoundException

The file does not exist.

IOException

The file is in use by another process, or an I/O error occurs.

PathTooLongException

The path exceeds the system-defined maximum length.

NotSupportedException

A file or directory name in the path contains a colon (:) or is in an invalid format.

OutOfMemoryException

There is not enough memory to write the string to buffer.

SecurityException

The user lacks necessary permissions to view the path.

Examples

This example reads the contents of Test.txt into a string and then displays it in a message box.

Dim reader = My.Computer.FileSystem.ReadAllText("C:\test.txt")
MsgBox(reader)

This example reads the contents of the ASCII file Test.txt into a string and then displays it in a message box.

Dim reader = My.Computer.FileSystem.ReadAllText("C:\test.txt",
   System.Text.Encoding.ASCII)
MsgBox(reader)

Remarks

The ReadAllText method of the My.Computer.FileSystem object allows you to read from a text file. The contents of the file are returned as a string.

The file encoding can be specified if the contents of the file are in an encoding such as ASCII or UTF-8. If you are reading from a file with extended characters, you need to specify the file encoding.

Do not make decisions about the contents of the file based on the name of the file. For example, the file Form1.vb may not be a Visual Basic source file. Verify all inputs before using the data in your application.

The following table lists examples of tasks involving the My.Computer.FileSystem.ReadAllText method.

To	See
Read from a text file	How to: Read from Text Files

See also

• Encoding
• StreamReader(Stream, Encoding)
• Objects (Visual Basic)
• Reading from Files in Visual Basic
• How to: Read Text from Files with a StreamReader (Visual Basic)
• Troubleshooting: Reading from and Writing to Text Files
• Walkthrough: Manipulating Files and Directories in Visual Basic
• File Encodings