Decimal.Round方法用于将值舍入到最接近的整数或指定数量的小数位数。此方法的重载列表中有4种方法,如下所示:

• Round(Decimal) 方法
• Round(Decimal,Int32)方法
• Round(Decimal, MidpointRounding) 方法
• Round(Decimal,Int32,MidpointRounding)方法

在这里,我们将讨论前两种方法。

Decimal.Round(Decimal) Method

此方法用于将十进制值舍入到最接近的整数。

用法: public static decimal Round (decimal d);
Here, it takes a decimal number to round.

返回值:此方法返回最接近d参数的整数。如果d在两个整数之间,其中一个是偶数,另一个是奇数,则返回偶数。

异常:如果结果超出Decimal值的范围,则此方法将引发OverflowException。

以下示例程序旨在说明Decimal.Round(Decimal)方法的用法:

范例1:

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System;   class GFG {       // Main Method     public static void Main()     {         try {               // Declaring and initializing value             decimal value = 184467440737095.51615M;               // getting rounded decimal             // using Round() method             decimal round = Decimal.Round(value);               // Display the value             Console.WriteLine("Rounded value is {0}", round);         }           catch (OverflowException e)          {             Console.WriteLine("Value must not be out of bound");             Console.Write("Exception Thrown:");             Console.Write("{0}", e.GetType(), e.Message);         }     } }

输出:

Rounded value is 184467440737096

范例2:对于OverflowException

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System;   class GFG {       // Main Method     public static void Main()     {           try         {               // Declaring and initializing value             decimal value = 79228162514264337593543950335.5M;               // getting rounded decimal             // using Round() method             decimal round = Decimal.Round(value);               // Display the value             Console.WriteLine("Rounded value is {0}", round);         }           catch (OverflowException e)          {             Console.WriteLine("Value must not be out of bound");             Console.Write("Exception Thrown:");             Console.Write("{0}", e.GetType(), e.Message);         }     } }

Compile-Time错误:

prog.cs(15,51):error CS0594:Floating-point constant is outside the range of type `decimal’

Round(Decimal, Int32) Method

此方法用于将十进制值舍入到指定的小数位数。

用法: public static decimal Round (decimal d, int decimals);

参数:
d:它是一个十进制数,将被四舍五入。
decimals:从0到28的值,指定要舍入到的小数位数。

返回值:此方法返回等于d的十进制数,四舍五入为小数位的小数位数。

异常:如果小数位数不是0到28之间的值,则此方法将引发ArgumentOutOfRangeException。

以下示例程序旨在说明Decimal.Round(Decimal,Int32)方法的用法:

范例1:

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System;   class GFG {       // Main Method     public static void Main()     {         try {               // Declaring and initializing value             decimal value = 7922816251426433759354.39503305M;               // getting rounded decimal             // using Round() method             decimal round = Decimal.Round(value, 4);               // Display the value             Console.WriteLine("Rounded value is {0}", round);         }           catch (ArgumentOutOfRangeException e)          {             Console.WriteLine("decimal place is not within bound");             Console.Write("Exception Thrown:");             Console.Write("{0}", e.GetType(), e.Message);         }     } }

输出:

Rounded value is 7922816251426433759354.3950

范例2:对于ArgumentOutOfRangeException

// C# program to demonstrate the // Decimal.Round(Decimal) Method using System;   class GFG {       // Main Method     public static void Main()     {         try         {               // Declaring and initializing value             decimal value = 7922816251426433759354.39503305M;               // getting rounded decimal             // using Round() method             decimal round = Decimal.Round(value, 29);               // Display the value             Console.WriteLine("Rounded value is {0}", round);         }           catch (ArgumentOutOfRangeException e)          {             Console.WriteLine("Decimal place is not within bound");             Console.Write("Exception Thrown:");             Console.Write("{0}", e.GetType(), e.Message);         }     } }

输出:

Decimal place is not within boundException Thrown:System.ArgumentOutOfRangeException

参考:

• https://docs.microsoft.com/en-us/dotnet/api/system.decimal.round?view=netframework-4.7.2