Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
ToInt64 Method

BitConverter.ToInt64 Method

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

Namespace:  System
Assemblies:   System.Runtime.Extensions (in System.Runtime.Extensions.dll)
  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 ToInt64 method converts the bytes from index startIndex to startIndex + 7 to a Int64 value. The order of bytes in the array must reflect the endianness of the computer system's architecture; for more information, see the Remarks section of the BitConverter class topic.

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
*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
Show:
© 2015 Microsoft