File.GetLastWriteTime() Method in C# with Examples

File.GetLastWriteTime(String) is an inbuilt File class method which is used to return the date and time the specified file or directory was last written to.
Syntax:

public static DateTime GetLastWriteTime (string path);

Parameter: This function accepts a parameter which is illustrated below: 

• path: This is the specified file path.

Exceptions:

• UnauthorizedAccessException: The caller does not have the required permission.
• ArgumentException: The path is a zero-length string, contains only white space, or one or more invalid characters as defined by InvalidPathChars.
• ArgumentNullException: The path is null.
• PathTooLongException: The given path, file name, or both exceed the system-defined maximum length.
• NotSupportedException: The path is in an invalid format.

Return Value: Returns the date and time the specified file or directory was last written to.
Below are the programs to illustrate the File.GetLastWriteTime(String) method.
Program 1: Before running the below code, a file file.txt is created with some contents shown below:

C#

// C# program to illustrate the usage
// of File.GetLastWriteTime(String) method

// Using System and System.IO namespaces
using System;
using System.IO;

class GFG {
    public static void Main()
    {
        // Specifying a file
        string myfile = @"file.txt";

        // Calling GetLastWriteTime() function
        DateTime dt = File.GetLastWriteTime(myfile);

        // Getting the last write time
        Console.WriteLine("The last write time for this file was {0}.", dt);
    }
}

Executing:

The last write time for this file was 4/19/2020 4:43:24 AM.

Program 2: Before running the below code, a file was created shown below:

C#

// C# program to illustrate the usage
// of File.GetLastWriteTime(String) method

// Using System and System.IO namespaces
using System;
using System.IO;

class GFG {
    public static void Main()
    {
        // Specifying a file
        string myfile = @"file.txt";

        // Setting the date
        File.SetLastWriteTime(myfile, new DateTime(2020, 4, 3));

        // Calling GetLastWriteTime() function
        DateTime dt = File.GetLastWriteTime(myfile);

        // Getting the last write time
        Console.WriteLine("The last write time for this file was {0}.", dt);
    }
}

Executing:

The last write time for this file was 4/3/2020 12:00:00 AM.