C＃中的DateTime.GetDateTimeFormats()方法|套装– 1

此方法用于将该实例的值转换为标准日期和时间格式说明符支持的所有字符串表示形式。此方法的重载列表中共有4种方法：

• GetDateTimeFormats()
• GetDateTimeFormats(字符)
• GetDateTimeFormats(IFormatProvider)
• GetDateTimeFormats(Char，IFormatProvider)

GetDateTimeFormats()

此方法用于将该实例的值转换为标准日期和时间格式说明符支持的所有字符串表示形式。

Syntax: public string[] GetDateTimeFormats ()

Return Value: This method returns a string array where each element is the representation of the value of this instance formatted with one of the standard date and time format specifiers.

下面的程序说明了GetDateTimeFormats()方法的用法：

范例1：

// C# program to demonstrate the
// DateTime.GetDateTimeFormats()
// Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
        // creating object of DateTime
        DateTime date = new DateTime(2010, 1,
                                     1, 4, 0, 15);
  
        // getting format in string array
        // using GetDateTimeFormats() method;
        string[] value = date.GetDateTimeFormats();
  
        // Print out value in all DateTime 
        // formats using the default culture.
        foreach(string format in value)
            Console.WriteLine(format);
    }
}

输出：

01/01/2010
2010-01-01
Friday, 01 January 2010
Friday, 01 January 2010 04:00
Friday, 01 January 2010 04:00 AM
Friday, 01 January 2010 4:00
Friday, 01 January 2010 4:00 AM
Friday, 01 January 2010 04:00:15
01/01/2010 04:00
01/01/2010 04:00 AM
01/01/2010 4:00
01/01/2010 4:00 AM
2010-01-01 04:00
2010-01-01 04:00 AM
2010-01-01 4:00
2010-01-01 4:00 AM
01/01/2010 04:00:15
2010-01-01 04:00:15
January 01
January 01
2010-01-01T04:00:15.0000000
2010-01-01T04:00:15.0000000
Fri, 01 Jan 2010 04:00:15 GMT
Fri, 01 Jan 2010 04:00:15 GMT
2010-01-01T04:00:15
04:00
04:00 AM
4:00
4:00 AM
04:00:15
2010-01-01 04:00:15Z
Friday, 01 January 2010 04:00:15
2010 January
2010 January

范例2：

// C# program to demonstrate the
// DateTime.GetDateTimeFormats()
// Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
        // creating object of DateTime
        DateTime date = new DateTime(2019, 1,
                              30, 9, 49, 15);
  
        // getting format in string array
        // using GetDateTimeFormats() method;
        string[] value = date.GetDateTimeFormats();
  
        // Print out value in all DateTime 
        // formats using the default culture.
        for (int i = 1; i <= 6; i++)
            Console.WriteLine(value[i]);
    }
}

输出：

2019-01-30
Wednesday, 30 January 2019
Wednesday, 30 January 2019 09:49
Wednesday, 30 January 2019 09:49 AM
Wednesday, 30 January 2019 9:49
Wednesday, 30 January 2019 9:49 AM

GetDateTimeFormats(字符)

此方法用于将该实例的值转换为指定的标准日期和时间格式说明符支持的所有字符串表示形式。

Syntax: public string[] GetDateTimeFormats (char format);
Here it takes a standard date and time format string.

Return Value: This method returns a string array where each element is the representation of the value of this instance formatted with the format standard date and time format specifier.

Exceptions: This method will give FormatException if the format is not a valid standard date and time format specifier character.

下面的程序说明了GetDateTimeFormats(Char)方法的用法：

范例1：

// C# program to demonstrate the
// DateTime.GetDateTimeFormats(Char)
// Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
        try {
            // creating object of DateTime
            DateTime date = new DateTime(2010, 1,
                                     1, 4, 0, 15);
  
            // Get the long date formats using the current
            // culture. using GetDateTimeFormats() method
            string[] value = date.GetDateTimeFormats('D');
  
            // Print out value in all DateTime
            // formats using the default culture.
            foreach(string format in value)
                Console.WriteLine(format);
        }
        catch (FormatException e) {
            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

输出：

Friday, 01 January 2010

示例2：对于FormatException

// C# program to demonstrate the
// DateTime.GetDateTimeFormats(Char)
// Method
using System;
using System.Globalization;
  
class GFG {
  
    // Main Method
    public static void Main()
    {
        try {
            // creating object of DateTime
            DateTime date = new DateTime(2010, 1,
                                         1, 4, 0, 15);
  
            // Get the date format
            // using GetDateTimeFormats(Char) method;
            string[] value = date.GetDateTimeFormats('X');
  
            // Print out value in all DateTime 
            // formats using the default culture.
            foreach(string format in value)
                Console.WriteLine(format);
        }
        catch (FormatException e) {
            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

输出：

Exception Thrown: System.FormatException

参考：

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