BitConverter.ToDouble 方法
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
多載
ToDouble(ReadOnlySpan<Byte>) |
將唯讀位元組範圍轉換為雙精確度浮點數值。 |
ToDouble(Byte[], Int32) |
傳回從位元組陣列中指定位置的八個位元組所轉換的雙精確度浮點數。 |
ToDouble(ReadOnlySpan<Byte>)
將唯讀位元組範圍轉換為雙精確度浮點數值。
public:
static double ToDouble(ReadOnlySpan<System::Byte> value);
public static double ToDouble (ReadOnlySpan<byte> value);
static member ToDouble : ReadOnlySpan<byte> -> double
Public Shared Function ToDouble (value As ReadOnlySpan(Of Byte)) As Double
參數
- value
- ReadOnlySpan<Byte>
包含要轉換之位元組的唯讀範圍。
傳回
代表已轉換之位元組的雙精確度浮點數值。
例外狀況
value
的長度小於 Double 值的長度。
適用於
ToDouble(Byte[], Int32)
傳回從位元組陣列中指定位置的八個位元組所轉換的雙精確度浮點數。
public:
static double ToDouble(cli::array <System::Byte> ^ value, int startIndex);
public static double ToDouble (byte[] value, int startIndex);
static member ToDouble : byte[] * int -> double
Public Shared Function ToDouble (value As Byte(), startIndex As Integer) As Double
參數
- value
- Byte[]
位元組陣列,包含要轉換的八個位元組。
- startIndex
- Int32
開始位置在 value
內。
傳回
由八個位元組組成的雙精確度浮點數,從 開始 startIndex
。
例外狀況
startIndex
大於或等於 value
的長度減去 7,而且小於或等於 value
的長度減去 1。
value
為 null
。
startIndex
小於零或大於 value
的長度減去 1。
範例
下列程式碼範例會使用 ToDouble
方法,將陣列 Double 的專案 Byte 轉換成值。
// Example of the BitConverter::ToDouble method.
using namespace System;
// Convert eight byte array elements to a double and display it.
void BAToDouble( array<unsigned char>^bytes, int index )
{
double value = BitConverter::ToDouble( bytes, index );
Console::WriteLine( "{0,5}{1,27}{2,27:E16}", index, BitConverter::ToString( bytes, index, 8 ), value );
}
// Display a byte array, using multiple lines if necessary.
void WriteMultiLineByteArray( array<unsigned char>^bytes )
{
const int rowSize = 20;
int iter;
Console::WriteLine( "initial unsigned char array" );
Console::WriteLine( "---------------------------" );
for ( iter = 0; iter < bytes->Length - rowSize; iter += rowSize )
{
Console::Write( BitConverter::ToString( bytes, iter, rowSize ) );
Console::WriteLine( "-" );
}
Console::WriteLine( BitConverter::ToString( bytes, iter ) );
Console::WriteLine();
}
int main()
{
array<unsigned char>^byteArray = {0,0,0,0,0,0,0,0,240,63,0,0,0,0,0,224,111,64,0,0,224,255,255,255,239,65,0,0,0,0,0,0,112,63,0,0,0,0,0,0,240,61,223,136,30,28,254,116,170,1,250,89,140,66,202,192,243,63,251,89,140,66,202,192,243,63,252,89,140,66,202,192,243,63,82,211,187,188,232,126,61,126,255,255,255,255,255,255,239,255,255,255,255,255,255,239,127,1,0,0,0,0,0,0,0,248,255,0,0,0,0,0,0,240,255,0,0,0,0,0,0,240,127};
Console::WriteLine( "This example of the BitConverter::ToDouble( unsigned "
"char[ ], int ) \nmethod generates the following output. It "
"converts elements of a \nbyte array to double values.\n" );
WriteMultiLineByteArray( byteArray );
Console::WriteLine( "{0,5}{1,27}{2,27:E16}", "index", "array elements", "double" );
Console::WriteLine( "{0,5}{1,27}{2,27:E16}", "-----", "--------------", "------" );
// Convert byte array elements to double values.
BAToDouble( byteArray, 0 );
BAToDouble( byteArray, 2 );
BAToDouble( byteArray, 10 );
BAToDouble( byteArray, 18 );
BAToDouble( byteArray, 26 );
BAToDouble( byteArray, 34 );
BAToDouble( byteArray, 42 );
BAToDouble( byteArray, 50 );
BAToDouble( byteArray, 58 );
BAToDouble( byteArray, 66 );
BAToDouble( byteArray, 74 );
BAToDouble( byteArray, 82 );
BAToDouble( byteArray, 89 );
BAToDouble( byteArray, 97 );
BAToDouble( byteArray, 99 );
BAToDouble( byteArray, 107 );
BAToDouble( byteArray, 115 );
}
/*
This example of the BitConverter.ToDouble( byte( ), int )
method generates the following output. It converts elements
of a byte array to double values.
initial byte array
------------------
00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
E0-FF-FF-FF-EF-41-00-00-00-00-00-00-70-3F-00-00-00-00-00-00-
F0-3D-DF-88-1E-1C-FE-74-AA-01-FA-59-8C-42-CA-C0-F3-3F-FB-59-
8C-42-CA-C0-F3-3F-FC-59-8C-42-CA-C0-F3-3F-52-D3-BB-BC-E8-7E-
3D-7E-FF-FF-FF-FF-FF-FF-EF-FF-FF-FF-FF-FF-FF-EF-7F-01-00-00-
00-00-00-00-00-F8-FF-00-00-00-00-00-00-F0-FF-00-00-00-00-00-
00-F0-7F
index array elements double
----- -------------- ------
0 00-00-00-00-00-00-00-00 0.0000000000000000E+000
2 00-00-00-00-00-00-F0-3F 1.0000000000000000E+000
10 00-00-00-00-00-E0-6F-40 2.5500000000000000E+002
18 00-00-E0-FF-FF-FF-EF-41 4.2949672950000000E+009
26 00-00-00-00-00-00-70-3F 3.9062500000000000E-003
34 00-00-00-00-00-00-F0-3D 2.3283064365386963E-010
42 DF-88-1E-1C-FE-74-AA-01 1.2345678901234500E-300
50 FA-59-8C-42-CA-C0-F3-3F 1.2345678901234565E+000
58 FB-59-8C-42-CA-C0-F3-3F 1.2345678901234567E+000
66 FC-59-8C-42-CA-C0-F3-3F 1.2345678901234569E+000
74 52-D3-BB-BC-E8-7E-3D-7E 1.2345678901234569E+300
82 FF-FF-FF-FF-FF-FF-EF-FF -1.7976931348623157E+308
89 FF-FF-FF-FF-FF-FF-EF-7F 1.7976931348623157E+308
97 01-00-00-00-00-00-00-00 4.9406564584124654E-324
99 00-00-00-00-00-00-F8-FF NaN
107 00-00-00-00-00-00-F0-FF -Infinity
115 00-00-00-00-00-00-F0-7F Infinity
*/
// Example of the BitConverter.ToDouble method.
using System;
class BytesToDoubleDemo
{
const string formatter = "{0,5}{1,27}{2,27:E16}";
// Convert eight byte array elements to a double and display it.
public static void BAToDouble( byte[ ] bytes, int index )
{
double value = BitConverter.ToDouble( bytes, index );
Console.WriteLine( formatter, index,
BitConverter.ToString( bytes, index, 8 ), value );
}
// Display a byte array, using multiple lines if necessary.
public static void WriteMultiLineByteArray( byte[ ] bytes )
{
const int rowSize = 20;
int iter;
Console.WriteLine( "initial byte array" );
Console.WriteLine( "------------------" );
for( iter = 0; iter < bytes.Length - rowSize; iter += rowSize )
{
Console.Write(
BitConverter.ToString( bytes, iter, rowSize ) );
Console.WriteLine( "-" );
}
Console.WriteLine( BitConverter.ToString( bytes, iter ) );
Console.WriteLine( );
}
public static void Main( )
{
byte[ ] byteArray = {
0, 0, 0, 0, 0, 0, 0, 0, 240, 63,
0, 0, 0, 0, 0, 224, 111, 64, 0, 0,
224, 255, 255, 255, 239, 65, 0, 0, 0, 0,
0, 0, 112, 63, 0, 0, 0, 0, 0, 0,
240, 61, 223, 136, 30, 28, 254, 116, 170, 1,
250, 89, 140, 66, 202, 192, 243, 63, 251, 89,
140, 66, 202, 192, 243, 63, 252, 89, 140, 66,
202, 192, 243, 63, 82, 211, 187, 188, 232, 126,
61, 126, 255, 255, 255, 255, 255, 255, 239, 255,
255, 255, 255, 255, 255, 239, 127, 1, 0, 0,
0, 0, 0, 0, 0, 248, 255, 0, 0, 0,
0, 0, 0, 240, 255, 0, 0, 0, 0, 0,
0, 240, 127 };
Console.WriteLine(
"This example of the BitConverter.ToDouble( byte[ ], " +
"int ) \nmethod generates the following output. It " +
"converts elements \nof a byte array to double values.\n" );
WriteMultiLineByteArray( byteArray );
Console.WriteLine( formatter, "index", "array elements",
"double" );
Console.WriteLine( formatter, "-----", "--------------",
"------" );
// Convert byte array elements to double values.
BAToDouble( byteArray, 0 );
BAToDouble( byteArray, 2 );
BAToDouble( byteArray, 10 );
BAToDouble( byteArray, 18 );
BAToDouble( byteArray, 26 );
BAToDouble( byteArray, 34 );
BAToDouble( byteArray, 42 );
BAToDouble( byteArray, 50 );
BAToDouble( byteArray, 58 );
BAToDouble( byteArray, 66 );
BAToDouble( byteArray, 74 );
BAToDouble( byteArray, 82 );
BAToDouble( byteArray, 89 );
BAToDouble( byteArray, 97 );
BAToDouble( byteArray, 99 );
BAToDouble( byteArray, 107 );
BAToDouble( byteArray, 115 );
}
}
/*
This example of the BitConverter.ToDouble( byte[ ], int )
method generates the following output. It converts elements
of a byte array to double values.
initial byte array
------------------
00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
E0-FF-FF-FF-EF-41-00-00-00-00-00-00-70-3F-00-00-00-00-00-00-
F0-3D-DF-88-1E-1C-FE-74-AA-01-FA-59-8C-42-CA-C0-F3-3F-FB-59-
8C-42-CA-C0-F3-3F-FC-59-8C-42-CA-C0-F3-3F-52-D3-BB-BC-E8-7E-
3D-7E-FF-FF-FF-FF-FF-FF-EF-FF-FF-FF-FF-FF-FF-EF-7F-01-00-00-
00-00-00-00-00-F8-FF-00-00-00-00-00-00-F0-FF-00-00-00-00-00-
00-F0-7F
index array elements double
----- -------------- ------
0 00-00-00-00-00-00-00-00 0.0000000000000000E+000
2 00-00-00-00-00-00-F0-3F 1.0000000000000000E+000
10 00-00-00-00-00-E0-6F-40 2.5500000000000000E+002
18 00-00-E0-FF-FF-FF-EF-41 4.2949672950000000E+009
26 00-00-00-00-00-00-70-3F 3.9062500000000000E-003
34 00-00-00-00-00-00-F0-3D 2.3283064365386963E-010
42 DF-88-1E-1C-FE-74-AA-01 1.2345678901234500E-300
50 FA-59-8C-42-CA-C0-F3-3F 1.2345678901234565E+000
58 FB-59-8C-42-CA-C0-F3-3F 1.2345678901234567E+000
66 FC-59-8C-42-CA-C0-F3-3F 1.2345678901234569E+000
74 52-D3-BB-BC-E8-7E-3D-7E 1.2345678901234569E+300
82 FF-FF-FF-FF-FF-FF-EF-FF -1.7976931348623157E+308
89 FF-FF-FF-FF-FF-FF-EF-7F 1.7976931348623157E+308
97 01-00-00-00-00-00-00-00 4.9406564584124654E-324
99 00-00-00-00-00-00-F8-FF NaN
107 00-00-00-00-00-00-F0-FF -Infinity
115 00-00-00-00-00-00-F0-7F Infinity
*/
open System
let print obj1 obj2 obj3 = printfn $"{obj1,5}{obj2,27}{obj3,27:E16}"
// Convert eight byte array elements to a double and display it.
let BAToDouble bytes index =
let value = BitConverter.ToDouble(bytes, index)
print index (BitConverter.ToString(bytes, index, 8)) value
// Display a byte array, using multiple lines if necessary.
let writeMultiLineByteArray (bytes: byte []) =
let rowSize = 20
printfn "initial byte array"
printfn "------------------"
let mutable iter = 0
for i in 0 .. rowSize .. (bytes.Length - rowSize - 1) do
printfn $"{BitConverter.ToString(bytes, iter, rowSize)}-"
iter <- i
printfn $"{BitConverter.ToString(bytes, iter + rowSize)}\n"
let byteArray =
[| 0uy; 0uy; 0uy; 0uy; 0uy; 0uy; 0uy; 0uy; 240uy; 63uy
0uy; 0uy; 0uy; 0uy; 0uy; 224uy; 111uy; 64uy; 0uy; 0uy;
224uy; 255uy; 255uy; 255uy; 239uy; 65uy; 0uy; 0uy; 0uy; 0uy
0uy; 0uy; 112uy; 63uy; 0uy; 0uy; 0uy; 0uy; 0uy; 0uy
240uy; 61uy; 223uy; 136uy; 30uy; 28uy; 254uy; 116uy; 170uy; 1uy
250uy; 89uy; 140uy; 66uy; 202uy; 192uy; 243uy; 63uy; 251uy; 89uy
140uy; 66uy; 202uy; 192uy; 243uy; 63uy; 252uy; 89uy; 140uy; 66uy
202uy; 192uy; 243uy; 63uy; 82uy; 211uy; 187uy; 188uy; 232uy; 126uy
61uy; 126uy; 255uy; 255uy; 255uy; 255uy; 255uy; 255uy; 239uy; 255uy
255uy; 255uy; 255uy; 255uy; 255uy; 239uy; 127uy; 1uy; 0uy; 0uy
0uy; 0uy; 0uy; 0uy; 0uy; 248uy; 255uy; 0uy; 0uy; 0uy
0uy; 0uy; 0uy; 240uy; 255uy; 0uy; 0uy; 0uy; 0uy; 0uy
0uy; 240uy; 127uy |]
printfn "This example of the BitConverter.ToDouble(byte [], int) \nmethod generates the following output. It converts elements \nof a byte array to double values.\n"
writeMultiLineByteArray byteArray
print "index" "array elements" "double"
print "-----" "--------------" "------"
// Convert byte array elements to double values.
BAToDouble byteArray 0
BAToDouble byteArray 2
BAToDouble byteArray 10
BAToDouble byteArray 18
BAToDouble byteArray 26
BAToDouble byteArray 34
BAToDouble byteArray 42
BAToDouble byteArray 50
BAToDouble byteArray 58
BAToDouble byteArray 66
BAToDouble byteArray 74
BAToDouble byteArray 82
BAToDouble byteArray 89
BAToDouble byteArray 97
BAToDouble byteArray 99
BAToDouble byteArray 107
BAToDouble byteArray 115
// This example of the BitConverter.ToDouble(byte [], int )
// method generates the following output. It converts elements
// of a byte array to double values.
// initial byte array
// ------------------
// 00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
// 00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
// E0-FF-FF-FF-EF-41-00-00-00-00-00-00-70-3F-00-00-00-00-00-00-
// F0-3D-DF-88-1E-1C-FE-74-AA-01-FA-59-8C-42-CA-C0-F3-3F-FB-59-
// 8C-42-CA-C0-F3-3F-FC-59-8C-42-CA-C0-F3-3F-52-D3-BB-BC-E8-7E-
// 3D-7E-FF-FF-FF-FF-FF-FF-EF-FF-FF-FF-FF-FF-FF-EF-7F-01-00-00-
// 00-F0-7F
//
// index array elements double
// ----- -------------- ------
// 0 00-00-00-00-00-00-00-00 0.0000000000000000E+000
// 2 00-00-00-00-00-00-F0-3F 1.0000000000000000E+000
// 10 00-00-00-00-00-E0-6F-40 2.5500000000000000E+002
// 18 00-00-E0-FF-FF-FF-EF-41 4.2949672950000000E+009
// 26 00-00-00-00-00-00-70-3F 3.9062500000000000E-003
// 34 00-00-00-00-00-00-F0-3D 2.3283064365386963E-010
// 42 DF-88-1E-1C-FE-74-AA-01 1.2345678901234500E-300
// 50 FA-59-8C-42-CA-C0-F3-3F 1.2345678901234565E+000
// 58 FB-59-8C-42-CA-C0-F3-3F 1.2345678901234567E+000
// 66 FC-59-8C-42-CA-C0-F3-3F 1.2345678901234569E+000
// 74 52-D3-BB-BC-E8-7E-3D-7E 1.2345678901234569E+300
// 82 FF-FF-FF-FF-FF-FF-EF-FF -1.7976931348623157E+308
// 89 FF-FF-FF-FF-FF-FF-EF-7F 1.7976931348623157E+308
// 97 01-00-00-00-00-00-00-00 4.9406564584124654E-324
// 99 00-00-00-00-00-00-F8-FF NaN
// 107 00-00-00-00-00-00-F0-FF -∞
// 115 00-00-00-00-00-00-F0-7F ∞
' Example of the BitConverter.ToDouble method.
Module BytesToDoubleDemo
Const formatter As String = "{0,5}{1,27}{2,27:E16}"
' Convert eight Byte array elements to a Double and display it.
Sub BAToDouble( bytes( ) As Byte, index As Integer )
Dim value As Double = BitConverter.ToDouble( bytes, index )
Console.WriteLine( formatter, index, _
BitConverter.ToString( bytes, index, 8 ), value )
End Sub
' Display a Byte array, using multiple lines if necessary.
Sub WriteMultiLineByteArray( bytes( ) As Byte )
Const rowSize As Integer = 20
Dim iter As Integer
Console.WriteLine( "initial Byte array" )
Console.WriteLine( "------------------" )
For iter = 0 To bytes.Length - rowSize - 1 Step rowSize
Console.Write( _
BitConverter.ToString( bytes, iter, rowSize ) )
Console.WriteLine( "-" )
Next iter
Console.WriteLine( BitConverter.ToString( bytes, iter ) )
Console.WriteLine( )
End Sub
Sub Main( )
Dim byteArray as Byte( ) = { _
0, 0, 0, 0, 0, 0, 0, 0, 240, 63, _
0, 0, 0, 0, 0, 224, 111, 64, 0, 0, _
224, 255, 255, 255, 239, 65, 0, 0, 0, 0, _
0, 0, 112, 63, 0, 0, 0, 0, 0, 0, _
240, 61, 223, 136, 30, 28, 254, 116, 170, 1, _
250, 89, 140, 66, 202, 192, 243, 63, 251, 89, _
140, 66, 202, 192, 243, 63, 252, 89, 140, 66, _
202, 192, 243, 63, 82, 211, 187, 188, 232, 126, _
61, 126, 255, 255, 255, 255, 255, 255, 239, 255, _
255, 255, 255, 255, 255, 239, 127, 1, 0, 0, _
0, 0, 0, 0, 0, 248, 255, 0, 0, 0, _
0, 0, 0, 240, 255, 0, 0, 0, 0, 0, _
0, 240, 127 }
Console.WriteLine( _
"This example of the BitConverter.ToDouble( Byte( ), " & _
"Integer ) " & vbCrLf & "method generates the " & _
"following output. It converts elements " & vbCrLf & _
"of a Byte array to Double values." & vbCrLf )
WriteMultiLineByteArray( byteArray )
Console.WriteLine( formatter, "index", "array elements", _
"Double" )
Console.WriteLine( formatter, "-----", "--------------", _
"------" )
' Convert Byte array elements to Double values.
BAToDouble( byteArray, 0 )
BAToDouble( byteArray, 2 )
BAToDouble( byteArray, 10 )
BAToDouble( byteArray, 18 )
BAToDouble( byteArray, 26 )
BAToDouble( byteArray, 34 )
BAToDouble( byteArray, 42 )
BAToDouble( byteArray, 50 )
BAToDouble( byteArray, 58 )
BAToDouble( byteArray, 66 )
BAToDouble( byteArray, 74 )
BAToDouble( byteArray, 82 )
BAToDouble( byteArray, 89 )
BAToDouble( byteArray, 97 )
BAToDouble( byteArray, 99 )
BAToDouble( byteArray, 107 )
BAToDouble( byteArray, 115 )
End Sub
End Module
' This example of the BitConverter.ToDouble( Byte( ), Integer )
' method generates the following output. It converts elements
' of a Byte array to Double values.
'
' initial Byte array
' ------------------
' 00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
' E0-FF-FF-FF-EF-41-00-00-00-00-00-00-70-3F-00-00-00-00-00-00-
' F0-3D-DF-88-1E-1C-FE-74-AA-01-FA-59-8C-42-CA-C0-F3-3F-FB-59-
' 8C-42-CA-C0-F3-3F-FC-59-8C-42-CA-C0-F3-3F-52-D3-BB-BC-E8-7E-
' 3D-7E-FF-FF-FF-FF-FF-FF-EF-FF-FF-FF-FF-FF-FF-EF-7F-01-00-00-
' 00-00-00-00-00-F8-FF-00-00-00-00-00-00-F0-FF-00-00-00-00-00-
' 00-F0-7F
'
' index array elements Double
' ----- -------------- ------
' 0 00-00-00-00-00-00-00-00 0.0000000000000000E+000
' 2 00-00-00-00-00-00-F0-3F 1.0000000000000000E+000
' 10 00-00-00-00-00-E0-6F-40 2.5500000000000000E+002
' 18 00-00-E0-FF-FF-FF-EF-41 4.2949672950000000E+009
' 26 00-00-00-00-00-00-70-3F 3.9062500000000000E-003
' 34 00-00-00-00-00-00-F0-3D 2.3283064365386963E-010
' 42 DF-88-1E-1C-FE-74-AA-01 1.2345678901234500E-300
' 50 FA-59-8C-42-CA-C0-F3-3F 1.2345678901234565E+000
' 58 FB-59-8C-42-CA-C0-F3-3F 1.2345678901234567E+000
' 66 FC-59-8C-42-CA-C0-F3-3F 1.2345678901234569E+000
' 74 52-D3-BB-BC-E8-7E-3D-7E 1.2345678901234569E+300
' 82 FF-FF-FF-FF-FF-FF-EF-FF -1.7976931348623157E+308
' 89 FF-FF-FF-FF-FF-FF-EF-7F 1.7976931348623157E+308
' 97 01-00-00-00-00-00-00-00 4.9406564584124654E-324
' 99 00-00-00-00-00-00-F8-FF NaN
' 107 00-00-00-00-00-00-F0-FF -Infinity
' 115 00-00-00-00-00-00-F0-7F Infinity
備註
方法會將 ToDouble 位元組從索引 startIndex
轉換為 startIndex
+ 7 轉換為 Double 值。 陣列中的位元組順序必須反映電腦系統架構的結束時間。 如需詳細資訊,請參閱類別主題的 BitConverter 一節。