File.WriteAllText Method (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 overwritten.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- path
- Type: System.String
The file to write to.
- contents
- Type: System.String
The string to write to the file.
- encoding
- Type: System.Text.Encoding
The encoding to apply to the string.
| Exception | Condition |
|---|---|
| ArgumentException |
path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars. |
| ArgumentNullException |
path is null or contents is empty. |
| PathTooLongException |
The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters. |
| DirectoryNotFoundException |
The specified path is invalid (for example, it is on an unmapped drive). |
| IOException |
An I/O error occurred while opening the file. |
| UnauthorizedAccessException |
path specified a file that is read-only. -or- This operation is not supported on the current platform. -or- path specified a directory. -or- The caller does not have the required permission. |
| FileNotFoundException |
The file specified in path was not found. |
| NotSupportedException |
path is in an invalid format. |
| SecurityException |
The caller does not have the required permission. |
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); } }
-
FileIOPermission
for access to write to a file or directory. Associated enumeration: FileIOPermissionAccess.Write
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
