Decimal.ToDouble(Decimal) 方法
定义
重要
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将指定的 Decimal 的值转换为等效的双精度浮点数。
public:
static double ToDouble(System::Decimal d);public static double ToDouble (decimal d);static member ToDouble : decimal -> doublePublic Shared Function ToDouble (d As Decimal) As Double参数
- d
- Decimal
要转换的十进制数。
返回
与 d 等效的双精度浮点数。
示例
下面的代码示例 Decimal 使用方法将数字转换为 Double 值 ToDouble 。
// Example of the Decimal::ToSingle and Decimal::ToDouble methods.
using namespace System;
#define formatter "{0,30}{1,17}{2,23}"
// Convert the Decimal argument; no exceptions are thrown.
void DecimalToSgl_Dbl( Decimal argument )
{
Object^ SingleValue;
Object^ DoubleValue;
// Convert the argument to a float value.
SingleValue = Decimal::ToSingle( argument );
// Convert the argument to a double value.
DoubleValue = Decimal::ToDouble( argument );
Console::WriteLine( formatter, argument, SingleValue, DoubleValue );
}
int main()
{
Console::WriteLine( "This example of the \n"
" Decimal::ToSingle( Decimal ) and \n"
" Decimal::ToDouble( Decimal ) \nmethods "
"generates the following output. It \ndisplays "
"several converted Decimal values.\n" );
Console::WriteLine( formatter, "Decimal argument", "float", "double" );
Console::WriteLine( formatter, "----------------", "-----", "------" );
// Convert Decimal values and display the results.
DecimalToSgl_Dbl( Decimal::Parse( "0.0000000000000000000000000001" ) );
DecimalToSgl_Dbl( Decimal::Parse( "0.0000000000123456789123456789" ) );
DecimalToSgl_Dbl( Decimal::Parse( "123" ) );
DecimalToSgl_Dbl( Decimal(123000000,0,0,false,6) );
DecimalToSgl_Dbl( Decimal::Parse( "123456789.123456789" ) );
DecimalToSgl_Dbl( Decimal::Parse( "123456789123456789123456789" ) );
DecimalToSgl_Dbl( Decimal::MinValue );
DecimalToSgl_Dbl( Decimal::MaxValue );
}
/*
This example of the
Decimal::ToSingle( Decimal ) and
Decimal::ToDouble( Decimal )
methods generates the following output. It
displays several converted Decimal values.
Decimal argument float double
---------------- ----- ------
0.0000000000000000000000000001 1E-28 1E-28
0.0000000000123456789123456789 1.234568E-11 1.23456789123457E-11
123 123 123
123.000000 123 123
123456789.123456789 1.234568E+08 123456789.123457
123456789123456789123456789 1.234568E+26 1.23456789123457E+26
-79228162514264337593543950335 -7.922816E+28 -7.92281625142643E+28
79228162514264337593543950335 7.922816E+28 7.92281625142643E+28
*/
// Example of the decimal.ToSingle and decimal.ToDouble methods.
using System;
class DecimalToSgl_DblDemo
{
static string formatter = "{0,30}{1,17}{2,23}";
// Convert the decimal argument; no exceptions are thrown.
public static void DecimalToSgl_Dbl( decimal argument )
{
object SingleValue;
object DoubleValue;
// Convert the argument to a float value.
SingleValue = decimal.ToSingle( argument );
// Convert the argument to a double value.
DoubleValue = decimal.ToDouble( argument );
Console.WriteLine( formatter, argument,
SingleValue, DoubleValue );
}
public static void Main( )
{
Console.WriteLine( "This example of the \n" +
" decimal.ToSingle( decimal ) and \n" +
" decimal.ToDouble( decimal ) \nmethods " +
"generates the following output. It \ndisplays " +
"several converted decimal values.\n" );
Console.WriteLine( formatter, "decimal argument",
"float", "double" );
Console.WriteLine( formatter, "----------------",
"-----", "------" );
// Convert decimal values and display the results.
DecimalToSgl_Dbl( 0.0000000000000000000000000001M );
DecimalToSgl_Dbl( 0.0000000000123456789123456789M );
DecimalToSgl_Dbl( 123M );
DecimalToSgl_Dbl( new decimal( 123000000, 0, 0, false, 6 ) );
DecimalToSgl_Dbl( 123456789.123456789M );
DecimalToSgl_Dbl( 123456789123456789123456789M );
DecimalToSgl_Dbl( decimal.MinValue );
DecimalToSgl_Dbl( decimal.MaxValue );
}
}
/*
This example of the
decimal.ToSingle( decimal ) and
decimal.ToDouble( decimal )
methods generates the following output. It
displays several converted decimal values.
decimal argument float double
---------------- ----- ------
0.0000000000000000000000000001 1E-28 1E-28
0.0000000000123456789123456789 1.234568E-11 1.23456789123457E-11
123 123 123
123.000000 123 123
123456789.123456789 1.234568E+08 123456789.123457
123456789123456789123456789 1.234568E+26 1.23456789123457E+26
-79228162514264337593543950335 -7.922816E+28 -7.92281625142643E+28
79228162514264337593543950335 7.922816E+28 7.92281625142643E+28
*/
' Example of the Decimal.ToSingle and Decimal.ToDouble methods.
Module DecimalToSgl_DblDemo
Dim formatter As String = "{0,30}{1,17}{2,23}"
' Convert the Decimal argument; no exceptions are thrown.
Sub DecimalToSgl_Dbl( argument As Decimal )
Dim SingleValue As Object
Dim DoubleValue As Object
' Convert the argument to a Single value.
SingleValue = Decimal.ToSingle( argument )
' Convert the argument to a Double value.
DoubleValue = Decimal.ToDouble( argument )
Console.WriteLine( formatter, argument, _
SingleValue, DoubleValue )
End Sub
Sub Main( )
Console.WriteLine( "This example of the " & vbCrLf & _
" Decimal.ToSingle( Decimal ) and " & vbCrLf & _
" Decimal.ToDouble( Decimal ) " & vbCrLf & "methods " & _
"generates the following output. It " & vbCrLf & _
"displays several converted Decimal values." & vbCrLf )
Console.WriteLine( formatter, "Decimal argument", _
"Single", "Double" )
Console.WriteLine( formatter, "----------------", _
"------", "------" )
' Convert Decimal values and display the results.
DecimalToSgl_Dbl( 0.0000000000000000000000000001D )
DecimalToSgl_Dbl( 0.0000000000112233445566778899D )
DecimalToSgl_Dbl( 123D )
DecimalToSgl_Dbl( New Decimal( 123000000, 0, 0, False, 6 ) )
DecimalToSgl_Dbl( 123456789.123456789D )
DecimalToSgl_Dbl( 123456789123456789123456789D )
DecimalToSgl_Dbl( Decimal.MinValue )
DecimalToSgl_Dbl( Decimal.MaxValue )
End Sub
End Module
' This example of the
' Decimal.ToSingle( Decimal ) and
' Decimal.ToDouble( Decimal )
' methods generates the following output. It
' displays several converted Decimal values.
'
' Decimal argument Single Double
' ---------------- ------ ------
' 0.0000000000000000000000000001 1E-28 1E-28
' 0.0000000000112233445566778899 1.122334E-11 1.12233445566779E-11
' 123 123 123
' 123.000000 123 123
' 123456789.123456789 1.234568E+08 123456789.123457
' 123456789123456789123456789 1.234568E+26 1.23456789123457E+26
' -79228162514264337593543950335 -7.922816E+28 -7.92281625142643E+28
' 79228162514264337593543950335 7.922816E+28 7.92281625142643E+28
注解
此操作可能会产生舍入错误，因为双精度浮点数的有效位数少于 Decimal 。
还可以 Decimal Double 使用赋值运算符将转换为值 Explicit 。 因为转换可能会丢失精度，所以必须在 c # 中使用强制转换运算符或在 Visual Basic 中使用转换函数。