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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 long ToInt64(
	array<unsigned char>^ value, 
	int startIndex
)

Parameters

value
Type: array<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 nullptr.

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 namespace System;

// Convert eight byte array elements to an __int64 and display it. 
void BAToInt64( array<unsigned char>^bytes, int index )
{
   __int64 value = BitConverter::ToInt64( bytes, index );
   Console::WriteLine( "{0,5}{1,27}{2,24}", 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 = {0,54,101,196,255,255,255,255,0,0,0,0,0,0,0,0,128,0,202,154,59,0,0,0,0,1,0,0,0,0,255,255,255,255,1,0,0,255,255,255,255,255,255,255,127,86,85,85,85,85,85,255,255,170,170,170,170,170,170,0,0,100,167,179,182,224,13,0,0,156,88,76,73,31,242};
   Console::WriteLine( "This example of the BitConverter::ToInt64( unsigned " 
   "char[ ], int ) \nmethod generates the following output. It " 
   "converts elements of a \nbyte array to __int64 values.\n" );
   WriteMultiLineByteArray( byteArray );
   Console::WriteLine( "{0,5}{1,27}{2,24}", "index", "array elements", "__int64" );
   Console::WriteLine( "{0,5}{1,27}{2,24}", "-----", "--------------", "-------" );

   // Convert byte array elements to __int64 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( unsigned char[ ], int )
method generates the following output. It converts elements of a
byte array to __int64 values.

initial unsigned char 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                 __int64
-----             --------------                 -------
    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, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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