C# File.SetLastWriteTimeUtc()用法及代码示例

File.SetLastWriteTimeUtc(String)是一个内置的File类方法，该方法用于设置指定文件最后写入的日期和时间(以协调世界时(UTC))。

用法:

public static void SetLastWriteTimeUtc (string path, DateTime lastWriteTime);

参数：此函数接受两个参数，如下所示：

path: This is the specified file for which to set the date and time information.

lastWriteTime: This is the specified last written date and time of the path that is expressed in UTC time.

异常：

ArgumentException：路径为长度为零的字符串，仅包含空格，或者由InvalidPathChars定义的一个或多个无效字符。
ArgumentNullException：路径为空。
PathTooLongException：指定的路径，文件名或两者都超过了system-defined的最大长度。
FileNotFoundException：找不到指定的路径。
UnauthorizedAccessException：调用者没有所需的权限。
NotSupportedException：路径格式无效。
ArgumentOutOfRangeException：lastWriteTime指定一个超出此操作允许的日期或时间范围的值。

下面是说明File.SetLastWriteTimeUtc(String，DateTime)方法的程序。

程序1:在运行下面的代码之前，将创建一个文件file.txt，其内容如下所示：

file.txt

// C# program to illustrate the usage 
// of File.SetLastWriteTimeUtc() method 
  
// Using System and System.IO namespaces 
using System; 
using System.IO; 
  
class GFG { 
    public static void Main() 
    { 
        // Specifing a file 
        string myfile = @"file.txt"; 
  
        // Calling the SetLastWriteTimeUtc() function 
        // to set last written date and time in UTC 
        File.SetLastWriteTimeUtc(myfile, new DateTime(2020, 
                                           5, 4, 4, 5, 7)); 
  
        // Getting the last written date and time 
        // expressed in UTC of the file 
        DateTime dt = File.GetLastWriteTimeUtc(myfile); 
        Console.WriteLine("The last written date and"+ 
           " time in UTC for this file was {0}.", dt); 
    } 
}

输出：

The last written date and time in UTC for this file was 5/4/2020 4:05:07 AM.

程序2:最初，没有创建文件。在代码下方，其自身创建文件file.txt并打印最后写入的日期和时间。

// C# program to illustrate the usage 
// of File.SetLastWriteTimeUtc() method 
  
// Using System and System.IO namespaces 
using System; 
using System.IO; 
  
class GFG { 
    public static void Main() 
    { 
        // Specifing a file 
        string path = @"file.txt"; 
  
        // Checking the existance of the file 
        if (!File.Exists(path)) { 
            File.Create(path); 
        } 
  
        // Calling the SetLastWriteTimeUtc() function 
        // to set last written date and time in UTC 
        File.SetLastWriteTimeUtc(path, new DateTime(2019, 
                                         5, 4, 4, 5, 7)); 
  
        // Getting the last written date and time in UTC 
        // of the specified file 
        DateTime dt = File.GetLastWriteTimeUtc(path); 
        Console.WriteLine("The last written date and time "+ 
                       "in UTC for this file was {0}.", dt); 
    } 
}

执行中：

The last written date and time in UTC for this file was 5/4/2019 4:05:07 AM.

相关用法

注：本文由纯净天空筛选整理自Kanchan_Ray大神的英文原创作品 File.SetLastWriteTimeUtc() Method in C# with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。