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BitConverter.ToInt64 Method

Returns a 64-bit signed integer converted from eight bytes at a specified position in a byte array.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static long ToInt64(
	byte[] value,
	int startIndex
)

Parameters

value
Type: System.Byte[]

An array of bytes.

startIndex
Type: System.Int32

The starting position within value.

Return Value

Type: System.Int64
A 64-bit signed integer formed by eight bytes beginning at startIndex.

ExceptionCondition
ArgumentException

startIndex is greater than or equal to the length of value minus 7, and is less than or equal to the length of value minus 1.

ArgumentNullException

value is null.

ArgumentOutOfRangeException

startIndex is less than zero or greater than the length of value minus 1.

The following code example converts elements of Byte arrays to Int64 values with the ToInt64 method.

// Example of the BitConverter.ToInt64 method. 
using System;

class BytesToInt64Demo
{
    const string formatter = "{0,5}{1,27}{2,24}";

    // Convert eight byte array elements to a long and display it. 
    public static void BAToInt64( byte[ ] bytes, int index )
    {
        long value = BitConverter.ToInt64( 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,  54, 101, 196, 255, 255, 255, 255,   0,   0,
              0,   0,   0,   0,   0,   0, 128,   0, 202, 154, 
             59,   0,   0,   0,   0,   1,   0,   0,   0,   0, 
            255, 255, 255, 255,   1,   0,   0, 255, 255, 255, 
            255, 255, 255, 255, 127,  86,  85,  85,  85,  85, 
             85, 255, 255, 170, 170, 170, 170, 170, 170,   0, 
              0, 100, 167, 179, 182, 224,  13,   0,   0, 156, 
             88,  76,  73,  31, 242 };

        Console.WriteLine( 
            "This example of the BitConverter.ToInt64( byte[ ], " +
            "int ) \nmethod generates the following output. It " +
            "converts elements \nof a byte array to long values.\r\n" );

        WriteMultiLineByteArray( byteArray );

        Console.WriteLine( formatter, "index", "array elements", "long" );
        Console.WriteLine( formatter, "-----", "--------------", "----" );

        // Convert byte array elements to long values.
        BAToInt64( byteArray, 8 );
        BAToInt64( byteArray, 5 );
        BAToInt64( byteArray, 34 );
        BAToInt64( byteArray, 17 );
        BAToInt64( byteArray, 0 );
        BAToInt64( byteArray, 21 );
        BAToInt64( byteArray, 26 );
        BAToInt64( byteArray, 53 );
        BAToInt64( byteArray, 45 );
        BAToInt64( byteArray, 59 );
        BAToInt64( byteArray, 67 );
        BAToInt64( byteArray, 37 );
        BAToInt64( byteArray, 9 );
    }
}

/*
This example of the BitConverter.ToInt64( byte[ ], int )
method generates the following output. It converts elements
of a byte array to long values.

initial byte array
------------------
00-36-65-C4-FF-FF-FF-FF-00-00-00-00-00-00-00-00-80-00-CA-9A-
3B-00-00-00-00-01-00-00-00-00-FF-FF-FF-FF-01-00-00-FF-FF-FF-
FF-FF-FF-FF-7F-56-55-55-55-55-55-FF-FF-AA-AA-AA-AA-AA-AA-00-
00-64-A7-B3-B6-E0-0D-00-00-9C-58-4C-49-1F-F2

index             array elements                    long
-----             --------------                    ----
    8    00-00-00-00-00-00-00-00                       0
    5    FF-FF-FF-00-00-00-00-00                16777215
   34    01-00-00-FF-FF-FF-FF-FF               -16777215
   17    00-CA-9A-3B-00-00-00-00              1000000000
    0    00-36-65-C4-FF-FF-FF-FF             -1000000000
   21    00-00-00-00-01-00-00-00              4294967296
   26    00-00-00-00-FF-FF-FF-FF             -4294967296
   53    AA-AA-AA-AA-AA-AA-00-00         187649984473770
   45    56-55-55-55-55-55-FF-FF        -187649984473770
   59    00-00-64-A7-B3-B6-E0-0D     1000000000000000000
   67    00-00-9C-58-4C-49-1F-F2    -1000000000000000000
   37    FF-FF-FF-FF-FF-FF-FF-7F     9223372036854775807
    9    00-00-00-00-00-00-00-80    -9223372036854775808
*/

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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