File.WriteAllText Method
Definition
Important
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Creates a new file, write the contents to the file, and then closes the file. If the target file already exists, it is truncated and overwritten.
Overloads
WriteAllText(String, ReadOnlySpan<Char>) |
Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is truncated and overwritten. |
WriteAllText(String, String) |
Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is truncated and overwritten. |
WriteAllText(String, ReadOnlySpan<Char>, Encoding) |
Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file. If the target file already exists, it is truncated and overwritten. |
WriteAllText(String, String, Encoding) |
Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file. If the target file already exists, it is truncated and overwritten. |
WriteAllText(String, ReadOnlySpan<Char>)
Creates a new file, writes the specified string to the file, and then closes the file.
If the target file already exists, it is truncated and overwritten.
public:
static void WriteAllText(System::String ^ path, ReadOnlySpan<char> contents);
public static void WriteAllText (string path, ReadOnlySpan<char> contents);
static member WriteAllText : string * ReadOnlySpan<char> -> unit
Public Shared Sub WriteAllText (path As String, contents As ReadOnlySpan(Of Char))
Parameters
- path
- String
The file to write to.
- contents
- ReadOnlySpan<Char>
The characters to write to the file.
Exceptions
path
is null
.
path
is empty.
The specified path, file name, or both exceed the system-defined maximum length.
The specified path is invalid (for example, it is on an unmapped drive).
An I/O error occurred while opening the file.
path
specified a file that is read-only.
-or-
path
specified a file that is hidden.
-or-
path
specified a directory.
-or-
This operation is not supported on the current platform.
The caller does not have the required permission.
path
is in an invalid format.
Remarks
This method uses UTF-8 encoding without a Byte-Order Mark (BOM), so using the GetPreamble() method will return an empty byte array. If it is necessary to include a UTF-8 identifier, such as a byte order mark, at the beginning of a file, use the WriteAllText(String, ReadOnlySpan<Char>, Encoding) method.
Applies to
WriteAllText(String, String)
- Source:
- File.cs
- Source:
- File.cs
- Source:
- File.cs
Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is truncated and overwritten.
public:
static void WriteAllText(System::String ^ path, System::String ^ contents);
public static void WriteAllText (string path, string contents);
public static void WriteAllText (string path, string? contents);
static member WriteAllText : string * string -> unit
Public Shared Sub WriteAllText (path As String, contents As String)
Parameters
- path
- String
The file to write to.
- contents
- String
The string to write to the file.
Exceptions
.NET Framework and .NET Core versions older than 2.1: path
is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.
path
is null
.
The specified path, file name, or both exceed the system-defined maximum length.
The specified path is invalid (for example, it is on an unmapped drive).
An I/O error occurred while opening the file.
path
specified a file that is read-only.
-or-
path
specified a file that is hidden.
-or-
This operation is not supported on the current platform.
-or-
path
specified a directory.
-or-
The caller does not have the required permission.
path
is in an invalid format.
The caller does not have the required permission.
Examples
The following code example demonstrates the use of the WriteAllText method to write text to a file. In this example a file is created, if it doesn't already exist, and text is added to it.
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\temp\MyTest.txt";
// This text is added only once to the file.
if (!File.Exists(path))
{
// Create a file to write to.
string createText = "Hello and Welcome" + Environment.NewLine;
File.WriteAllText(path, createText);
}
// This text is always added, making the file longer over time
// if it is not deleted.
string appendText = "This is extra text" + Environment.NewLine;
File.AppendAllText(path, appendText);
// Open the file to read from.
string readText = File.ReadAllText(path);
Console.WriteLine(readText);
}
}
open System
open System.IO
let path = @"c:\temp\MyTest.txt"
// This text is added only once to the file.
if File.Exists path |> not then
// Create a file to write to.
let createText =
"Hello and Welcome" + Environment.NewLine
File.WriteAllText(path, createText)
// This text is always added, making the file longer over time
// if it is not deleted.
let appendText =
"This is extra text" + Environment.NewLine
File.AppendAllText(path, appendText)
// Open the file to read from.
let readText = File.ReadAllText path
printfn $"{readText}"
Imports System.IO
Imports System.Text
Public Class Test
Public Shared Sub Main()
Dim path As String = "c:\temp\MyTest.txt"
' This text is added only once to the file.
If File.Exists(path) = False Then
' Create a file to write to.
Dim createText As String = "Hello and Welcome" + Environment.NewLine
File.WriteAllText(path, createText)
End If
' This text is always added, making the file longer over time
' if it is not deleted.
Dim appendText As String = "This is extra text" + Environment.NewLine
File.AppendAllText(path, appendText)
' Open the file to read from.
Dim readText As String = File.ReadAllText(path)
Console.WriteLine(readText)
End Sub
End Class
Remarks
This method uses UTF-8 encoding without a Byte-Order Mark (BOM), so using the GetPreamble method will return an empty byte array. If it is necessary to include a UTF-8 identifier, such as a byte order mark, at the beginning of a file, use the WriteAllText(String, String, Encoding) method overload with UTF8 encoding.
Given a string and a file path, this method opens the specified file, writes the string to the file, and then closes the file.
Applies to
WriteAllText(String, ReadOnlySpan<Char>, Encoding)
Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file.
If the target file already exists, it is truncated and overwritten.
public:
static void WriteAllText(System::String ^ path, ReadOnlySpan<char> contents, System::Text::Encoding ^ encoding);
public static void WriteAllText (string path, ReadOnlySpan<char> contents, System.Text.Encoding encoding);
static member WriteAllText : string * ReadOnlySpan<char> * System.Text.Encoding -> unit
Public Shared Sub WriteAllText (path As String, contents As ReadOnlySpan(Of Char), encoding As Encoding)
Parameters
- path
- String
The file to write to.
- contents
- ReadOnlySpan<Char>
The characters to write to the file.
- encoding
- Encoding
The encoding to apply to the string.
Exceptions
path
or encoding
is null
.
path
is empty.
The specified path, file name, or both exceed the system-defined maximum length.
The specified path is invalid (for example, it is on an unmapped drive).
An I/O error occurred while opening the file.
path
specified a file that is read-only.
-or-
path
specified a file that is hidden.
-or-
path
specified a directory.
-or-
The caller does not have the required permission.
-or-
This operation is not supported on the current platform.
path
is in an invalid format.
Applies to
WriteAllText(String, String, Encoding)
- Source:
- File.cs
- Source:
- File.cs
- Source:
- File.cs
Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file. If the target file already exists, it is truncated and overwritten.
public:
static void WriteAllText(System::String ^ path, System::String ^ contents, System::Text::Encoding ^ encoding);
public static void WriteAllText (string path, string contents, System.Text.Encoding encoding);
public static void WriteAllText (string path, string? contents, System.Text.Encoding encoding);
static member WriteAllText : string * string * System.Text.Encoding -> unit
Public Shared Sub WriteAllText (path As String, contents As String, encoding As Encoding)
Parameters
- path
- String
The file to write to.
- contents
- String
The string to write to the file.
- encoding
- Encoding
The encoding to apply to the string.
Exceptions
.NET Framework and .NET Core versions older than 2.1: path
is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.
path
is null
.
The specified path, file name, or both exceed the system-defined maximum length.
The specified path is invalid (for example, it is on an unmapped drive).
An I/O error occurred while opening the file.
path
specified a file that is read-only.
-or-
path
specified a file that is hidden.
-or-
This operation is not supported on the current platform.
-or-
path
specified a directory.
-or-
The caller does not have the required permission.
path
is in an invalid format.
The caller does not have the required permission.
Examples
The following code example demonstrates the use of the WriteAllText method to write text to a file. In this example a file is created, if it doesn't already exist, and text is added to it.
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\temp\MyTest.txt";
// This text is added only once to the file.
if (!File.Exists(path))
{
// Create a file to write to.
string createText = "Hello and Welcome" + Environment.NewLine;
File.WriteAllText(path, createText, Encoding.UTF8);
}
// This text is always added, making the file longer over time
// if it is not deleted.
string appendText = "This is extra text" + Environment.NewLine;
File.AppendAllText(path, appendText, Encoding.UTF8);
// Open the file to read from.
string readText = File.ReadAllText(path);
Console.WriteLine(readText);
}
}
open System
open System.IO
open System.Text
let path = @"c:\temp\MyTest.txt"
// This text is added only once to the file.
if File.Exists path |> not then
// Create a file to write to.
let createText =
"Hello and Welcome" + Environment.NewLine
File.WriteAllText(path, createText, Encoding.UTF8)
// This text is always added, making the file longer over time
// if it is not deleted.
let appendText =
"This is extra text" + Environment.NewLine
File.AppendAllText(path, appendText, Encoding.UTF8)
// Open the file to read from.
let readText = File.ReadAllText path
printfn $"{readText}"
Imports System.IO
Imports System.Text
Public Class Test
Public Shared Sub Main()
Dim path As String = "c:\temp\MyTest.txt"
Dim sw As StreamWriter
' This text is added only once to the file.
If File.Exists(path) = False Then
' Create a file to write to.
Dim createText As String = "Hello and Welcome" + Environment.NewLine
File.WriteAllText(path, createText, Encoding.UTF8)
End If
' This text is always added, making the file longer over time
' if it is not deleted.
Dim appendText As String = "This is extra text" + Environment.NewLine
File.AppendAllText(path, appendText, Encoding.UTF8)
' Open the file to read from.
Dim readText As String = File.ReadAllText(path)
Console.WriteLine(readText)
End Sub
End Class
Remarks
Given a string and a file path, this method opens the specified file, writes the string to the file using the specified encoding, and then closes the file. The file handle is guaranteed to be closed by this method, even if exceptions are raised.
Applies to
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