C＃中的DateTime.FromFileTime()方法

DateTime.FromFileTime(Int64)方法用于将指定的Windows文件时间转换为等效的本地时间。

Syntax: public static DateTime FromFileTime (long fileTime);
Here, it takes a Windows file time expressed in ticks.

Return Value: This method returns an object that represents the local time equivalent of the date and time represented by the fileTime parameter.

Exception: This method will give ArgumentOutOfRangeException if the fileTime is less than 0 or represents a time greater than MaxValue.

下面的程序说明了DateTime.FromFileTime(Int64)方法的用法：

范例1：

// C# program to demonstrate the
// DateTime.FromFileTime(Int64) Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
        try {
  
            // creating object of DateTime
            DateTime date1 = new DateTime(2010, 3, 14, 2, 30, 00);
  
            // converting 2500000000000 file 
            // time represented in ticks
            // into DateTime format
            // using FromBinary() method
            DateTime date2 = DateTime.FromFileTime(2500000000000);
  
            // Display the date1
            System.Console.WriteLine("DateTime before "
                   + "operation: {0:y} {0:dd}", date1);
                                      
  
            // Display the date2
            System.Console.WriteLine("\nDateTime after"
                   + " operation: {0:y} {0:dd}", date2);
                                      
        }
  
        catch (ArgumentOutOfRangeException e) 
        {
            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

输出：

DateTime before operation: 2010 March 14

DateTime after operation: 1601 January 03

示例2：对于ArgumentOutOfRangeException

// C# program to demonstrate the
// DateTime.FromFileTime() Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
  
        try {
  
            // creating object of DateTime
            DateTime date1 = new DateTime(2010, 3,
                                   14, 2, 30, 00);
  
            // converting -1 file time 
            // represented in ticks
            // into DateTime format
            // using FromBinary() method
            DateTime date2 = DateTime.FromFileTime(-1);
  
            // Display the date1
            System.Console.WriteLine("DateTime before "
                     + "operation: {0:y} {0:dd}",date1);
                                       
  
            // Display the date2
            System.Console.WriteLine("\nDateTime after"
                   + " operation: {0:y} {0:dd}", date2);
                                      
        }
  
        catch (ArgumentOutOfRangeException e) {
            Console.WriteLine("fileTime is less than 0 ");
            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

输出：

fileTime is less than 0 
Exception Thrown: System.ArgumentOutOfRangeException

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.datetime.fromfiletime?view=netframework-4.7.2