Decimal の新しいインスタンスを作成し、その値を、指定した倍精度浮動小数点数に設定します。
名前空間: System
アセンブリ: mscorlib (mscorlib.dll 内)
構文
'宣言
Public Sub New ( _
value As Double _
)
'使用
Dim value As Double
Dim instance As New Decimal(value)
public Decimal (
double value
)
public:
Decimal (
double value
)
public Decimal (
double value
)
public function Decimal (
value : double
)
パラメータ
- value
Decimal として表す値。
例外
| 例外の種類 | 条件 |
|---|---|
value が MaxValue より大きい値か、MinValue より小さい値です。 または value が Double.NaN、Double.PositiveInfinity、または Double.NegativeInfinity です。 |
解説
このコンストラクタは、value を有効桁数 15 の近似値に丸めます。数値が 15 桁を超える場合でもこの丸めが行われ、15 桁より下位の桁は 0 になります。
使用例
Decimal 構造体を Double 値で初期化するコンストラクタのオーバーロードを使用して、複数の Decimal 数値を作成するコード例を次に示します。
' Example of the Decimal( Double ) constructor.
Imports System
Imports Microsoft.VisualBasic
Module DecimalCtorDoDemo
' Get the exception type name; remove the namespace prefix.
Function GetExceptionType( ex As Exception ) As String
Dim exceptionType As String = ex.GetType( ).ToString( )
Return exceptionType.Substring( _
exceptionType.LastIndexOf( "."c ) + 1 )
End Function
' Create a Decimal object and display its value.
Sub CreateDecimal( value As Double, valToStr As String )
' Format and display the constructor.
Console.Write( "{0,-34}", _
String.Format( "Decimal( {0} )", valToStr ) )
' Construct the Decimal value.
Try
Dim decimalNum As New Decimal( value )
' Display the value if it was created successfully.
Console.WriteLine( "{0,31}", decimalNum )
' Display the exception type if an exception was thrown.
Catch ex As Exception
Console.WriteLine( "{0,31}", GetExceptionType( ex ) )
End Try
End Sub
Sub Main( )
Console.WriteLine( _
"This example of the Decimal( Double ) constructor " & _
vbCrLf & "generates the following output." & vbCrLf )
Console.WriteLine( "{0,-34}{1,31}", "Constructor", _
"Value or Exception" )
Console.WriteLine( "{0,-34}{1,31}", "-----------", _
"------------------" )
' Construct Decimal objects from Double values.
CreateDecimal( 1.23456789E+5, "1.23456789E+5" )
CreateDecimal( 1.234567890123E+15, "1.234567890123E+15" )
CreateDecimal( 1.2345678901234567E+25, _
"1.2345678901234567E+25" )
CreateDecimal( 1.2345678901234567E+35, _
"1.2345678901234567E+35" )
CreateDecimal( 1.23456789E-5, "1.23456789E-5" )
CreateDecimal( 1.234567890123E-15, "1.234567890123E-15" )
CreateDecimal( 1.2345678901234567E-25, _
"1.2345678901234567E-25" )
CreateDecimal( 1.2345678901234567E-35, _
"1.2345678901234567E-35" )
CreateDecimal( 1.0 / 7.0, "1.0 / 7.0" )
End Sub
End Module
' This example of the Decimal( Double ) constructor
' generates the following output.
'
' Constructor Value or Exception
' ----------- ------------------
' Decimal( 1.23456789E+5 ) 123456.789
' Decimal( 1.234567890123E+15 ) 1234567890123000
' Decimal( 1.2345678901234567E+25 ) 12345678901234600000000000
' Decimal( 1.2345678901234567E+35 ) OverflowException
' Decimal( 1.23456789E-5 ) 0.0000123456789
' Decimal( 1.234567890123E-15 ) 0.000000000000001234567890123
' Decimal( 1.2345678901234567E-25 ) 0.0000000000000000000000001235
' Decimal( 1.2345678901234567E-35 ) 0
' Decimal( 1.0 / 7.0 ) 0.142857142857143
// Example of the decimal( double ) constructor.
using System;
class DecimalCtorDoDemo
{
// Get the exception type name; remove the namespace prefix.
public static string GetExceptionType( Exception ex )
{
string exceptionType = ex.GetType( ).ToString( );
return exceptionType.Substring(
exceptionType.LastIndexOf( '.' )+1 );
}
// Create a decimal object and display its value.
public static void CreateDecimal( double value, string valToStr )
{
// Format and display the constructor.
Console.Write( "{0,-34}",
String.Format( "decimal( {0} )", valToStr ) );
try
{
// Construct the decimal value.
decimal decimalNum = new decimal( value );
// Display the value if it was created successfully.
Console.WriteLine( "{0,31}", decimalNum );
}
catch( Exception ex )
{
// Display the exception type if an exception was thrown.
Console.WriteLine( "{0,31}", GetExceptionType( ex ) );
}
}
public static void Main( )
{
Console.WriteLine( "This example of the decimal( double ) " +
"constructor \ngenerates the following output.\n" );
Console.WriteLine( "{0,-34}{1,31}", "Constructor",
"Value or Exception" );
Console.WriteLine( "{0,-34}{1,31}", "-----------",
"------------------" );
// Construct decimal objects from double values.
CreateDecimal( 1.23456789E+5, "1.23456789E+5" );
CreateDecimal( 1.234567890123E+15, "1.234567890123E+15" );
CreateDecimal( 1.2345678901234567E+25,
"1.2345678901234567E+25" );
CreateDecimal( 1.2345678901234567E+35,
"1.2345678901234567E+35" );
CreateDecimal( 1.23456789E-5, "1.23456789E-5" );
CreateDecimal( 1.234567890123E-15, "1.234567890123E-15" );
CreateDecimal( 1.2345678901234567E-25,
"1.2345678901234567E-25" );
CreateDecimal( 1.2345678901234567E-35,
"1.2345678901234567E-35" );
CreateDecimal( 1.0 / 7.0, "1.0 / 7.0" );
}
}
/*
This example of the decimal( double ) constructor
generates the following output.
Constructor Value or Exception
----------- ------------------
decimal( 1.23456789E+5 ) 123456.789
decimal( 1.234567890123E+15 ) 1234567890123000
decimal( 1.2345678901234567E+25 ) 12345678901234600000000000
decimal( 1.2345678901234567E+35 ) OverflowException
decimal( 1.23456789E-5 ) 0.0000123456789
decimal( 1.234567890123E-15 ) 0.000000000000001234567890123
decimal( 1.2345678901234567E-25 ) 0.0000000000000000000000001235
decimal( 1.2345678901234567E-35 ) 0
decimal( 1.0 / 7.0 ) 0.142857142857143
*/
// Example of the Decimal( double ) constructor.
using namespace System;
// Get the exception type name; remove the namespace prefix.
String^ GetExceptionType( Exception^ ex )
{
String^ exceptionType = ex->GetType()->ToString();
return exceptionType->Substring( exceptionType->LastIndexOf( '.' ) + 1 );
}
// Create a Decimal object and display its value.
void CreateDecimal( double value, String^ valToStr )
{
// Format and display the constructor.
Console::Write( "{0,-34}", String::Format( "Decimal( {0} )", valToStr ) );
try
{
// Construct the Decimal value.
Decimal decimalNum = Decimal(value);
// Display the value if it was created successfully.
Console::WriteLine( "{0,31}", decimalNum );
}
catch ( Exception^ ex )
{
// Display the exception type if an exception was thrown.
Console::WriteLine( "{0,31}", GetExceptionType( ex ) );
}
}
int main()
{
Console::WriteLine( "This example of the Decimal( double ) "
"constructor \ngenerates the following output.\n" );
Console::WriteLine( "{0,-34}{1,31}", "Constructor", "Value or Exception" );
Console::WriteLine( "{0,-34}{1,31}", "-----------", "------------------" );
// Construct Decimal objects from double values.
CreateDecimal( 1.23456789E+5, "1.23456789E+5" );
CreateDecimal( 1.234567890123E+15, "1.234567890123E+15" );
CreateDecimal( 1.2345678901234567E+25, "1.2345678901234567E+25" );
CreateDecimal( 1.2345678901234567E+35, "1.2345678901234567E+35" );
CreateDecimal( 1.23456789E-5, "1.23456789E-5" );
CreateDecimal( 1.234567890123E-15, "1.234567890123E-15" );
CreateDecimal( 1.2345678901234567E-25, "1.2345678901234567E-25" );
CreateDecimal( 1.2345678901234567E-35, "1.2345678901234567E-35" );
CreateDecimal( 1.0 / 7.0, "1.0 / 7.0" );
}
/*
This example of the Decimal( double ) constructor
generates the following output.
Constructor Value or Exception
----------- ------------------
Decimal( 1.23456789E+5 ) 123456.789
Decimal( 1.234567890123E+15 ) 1234567890123000
Decimal( 1.2345678901234567E+25 ) 12345678901234600000000000
Decimal( 1.2345678901234567E+35 ) OverflowException
Decimal( 1.23456789E-5 ) 0.0000123456789
Decimal( 1.234567890123E-15 ) 0.000000000000001234567890123
Decimal( 1.2345678901234567E-25 ) 0.0000000000000000000000001235
Decimal( 1.2345678901234567E-35 ) 0
Decimal( 1.0 / 7.0 ) 0.142857142857143
*/
// Example of the decimal( double ) constructor.
import System.* ;
class DecimalCtorDoDemo
{
// Get the exception type name; remove the namespace prefix.
public static String GetExceptionType(System.Exception ex)
{
String exceptionType = ex.GetType().ToString();
return exceptionType.Substring((exceptionType.LastIndexOf('.') + 1)) ;
} //GetExceptionType
// Create a decimal object and display its value.
public static void CreateDecimal(double value, String valToStr)
{
// Format and display the constructor.
Console.Write("{0,-34}", String.Format("decimal( {0} )", valToStr));
try {
// Construct the decimal value.
System.Decimal decimalNum = new System.Decimal(value);
// Display the value if it was created successfully.
Console.WriteLine("{0,31}", decimalNum);
}
catch(System.Exception ex) {
// Display the exception type if an exception was thrown.
Console.WriteLine("{0,31}", GetExceptionType(ex));
}
} //CreateDecimal
public static void main(String[] args)
{
Console.WriteLine(("This example of the decimal( double ) "
+ "constructor \ngenerates the following output.\n"));
Console.WriteLine("{0,-34}{1,31}", "Constructor", "Value or Exception");
Console.WriteLine("{0,-34}{1,31}", "-----------", "------------------");
// Construct decimal objects from double values.
CreateDecimal(123456.789, "1.23456789E+5");
CreateDecimal(1.234567890123E+15 , "1.234567890123E+15");
CreateDecimal(1.23456789012346E+25, "1.2345678901234567E+25");
CreateDecimal(1.23456789012346E+35, "1.2345678901234567E+35");
CreateDecimal(1.23456789E-05, "1.23456789E-5");
CreateDecimal(1.234567890123E-15, "1.234567890123E-15");
CreateDecimal(1.23456789012346E-25, "1.2345678901234567E-25");
CreateDecimal(1.23456789012346E-35, "1.2345678901234567E-35");
CreateDecimal(1.0 / 7.0, "1.0 / 7.0");
} //main
} //DecimalCtorDoDemo
/*
This example of the decimal( double ) constructor
generates the following output.
Constructor Value or Exception
----------- ------------------
decimal( 1.23456789E+5 ) 123456.789
decimal( 1.234567890123E+15 ) 1234567890123000
decimal( 1.2345678901234567E+25 ) 12345678901234600000000000
decimal( 1.2345678901234567E+35 ) OverflowException
decimal( 1.23456789E-5 ) 0.0000123456789
decimal( 1.234567890123E-15 ) 0.000000000000001234567890123
decimal( 1.2345678901234567E-25 ) 0.0000000000000000000000001235
decimal( 1.2345678901234567E-35 ) 0
decimal( 1.0 / 7.0 ) 0.142857142857143
*/
プラットフォーム
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。
バージョン情報
.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0