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BitConverter.ToDouble Metodo

Definizione

Overload

ToDouble(ReadOnlySpan<Byte>)

Converte un intervallo di byte di sola lettura in un valore a virgola mobile e precisione doppia.

ToDouble(Byte[], Int32)

Restituisce un numero in virgola mobile e precisione doppia convertito da otto byte nella posizione specificata in una matrice di byte.

ToDouble(ReadOnlySpan<Byte>)

Converte un intervallo di byte di sola lettura in un valore a virgola mobile e precisione doppia.

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

Parametri

value
ReadOnlySpan<Byte>

Intervallo di sola lettura contenente i byte da convertire.

Restituisce

Double

Valore a virgola mobile e precisione doppia che rappresenta i byte convertiti.

Eccezioni

La lunghezza di value è minore della lunghezza di un valore Double.

Si applica a

ToDouble(Byte[], Int32)

Restituisce un numero in virgola mobile e precisione doppia convertito da otto byte nella posizione specificata in una matrice di byte.

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

Parametri

value
Byte[]

Matrice di byte che include gli otto byte da convertire.

startIndex
Int32

Posizione iniziale all'interno di value.

Restituisce

Double

Numero a virgola mobile a precisione doppia formato da otto byte a partire da startIndex.

Eccezioni

startIndex è maggiore o uguale alla lunghezza di value meno 7 e minore o uguale alla lunghezza di value meno 1.

value è null.

startIndexè minore di zero o maggiore della lunghezza di value meno 1.

Esempio

Nell'esempio di codice seguente vengono convertiti elementi di Byte matrici in Double valori con il ToDouble metodo .

// 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

Commenti

Il ToDouble metodo converte i byte dall'indice startIndex a startIndex + 7 in un Double valore. L'ordine dei byte nella matrice deve riflettere l'endianità dell'architettura del sistema computer. Per altre informazioni, vedere la sezione Osservazioni dell'argomento BitConverter della classe.

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