BitConverter.ToUInt64 Method (Byte(), Int32)

 

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

This API is not CLS-compliant.

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

<CLSCompliantAttribute(False)>
Public Shared Function ToUInt64 (
	value As Byte(),
	startIndex As Integer
) As ULong

Parameters

value
Type: System.Byte()

An array of bytes.

startIndex
Type: System.Int32

The starting position within value.

Return Value

Type: System.UInt64

A 64-bit unsigned integer formed by the eight bytes beginning at startIndex.

Exception Condition
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 ToUInt64 method converts the bytes from index startIndex to startIndex + 7 to a UInt64 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 UInt64 values with the ToUInt64 method.

' Example of the BitConverter.ToUInt64 method.
Imports System
Imports Microsoft.VisualBasic

Module BytesToUInt64Demo

    Const formatter As String = "{0,5}{1,27}{2,24}"

    ' Convert eight Byte array elements to a UInt64 and display it.
    Sub BAToUInt64( bytes( ) As Byte, index As Integer )

        Dim value As UInt64 = BitConverter.ToUInt64( 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( ) = { _
            255, 255, 255,   0,   0,   0,   0,   0,   0,   0, _
              0,   1,   0,   0,   0, 100, 167, 179, 182, 224, _
             13,   0, 202, 154,  59,   0,   0,   0,   0, 170, _
            170, 170, 170, 170, 170,   0,   0, 232, 137,   4, _
             35, 199, 138, 255, 255, 255, 255, 255, 255, 255, _
            255, 127 }

        Console.WriteLine( _
            "This example of the BitConverter.ToUInt64( Byte( ), " & _
            "Integer ) " & vbCrLf & "method generates the " & _
            "following output. It converts elements " & vbCrLf & _
            "of a Byte array to UInt64 values." & vbCrLf )

        WriteMultiLineByteArray( byteArray )

        Console.WriteLine( formatter, "index", "array elements", _
            "UInt64" )
        Console.WriteLine( formatter, "-----", "--------------", _
            "------" )

        ' Convert Byte array elements to UInt64 values.
        BAToUInt64( byteArray, 3 )
        BAToUInt64( byteArray, 0 )
        BAToUInt64( byteArray, 21 )
        BAToUInt64( byteArray, 7 )
        BAToUInt64( byteArray, 29 )
        BAToUInt64( byteArray, 13 )
        BAToUInt64( byteArray, 35 )
        BAToUInt64( byteArray, 44 )
        BAToUInt64( byteArray, 43 )
    End Sub 
End Module

' This example of the BitConverter.ToUInt64( Byte( ), Integer )
' method generates the following output. It converts elements
' of a Byte array to UInt64 values.
' 
' initial Byte array
' ------------------
' FF-FF-FF-00-00-00-00-00-00-00-00-01-00-00-00-64-A7-B3-B6-E0-
' 0D-00-CA-9A-3B-00-00-00-00-AA-AA-AA-AA-AA-AA-00-00-E8-89-04-
' 23-C7-8A-FF-FF-FF-FF-FF-FF-FF-FF-7F
' 
' index             array elements                  UInt64
' -----             --------------                  ------
'     3    00-00-00-00-00-00-00-00                       0
'     0    FF-FF-FF-00-00-00-00-00                16777215
'    21    00-CA-9A-3B-00-00-00-00              1000000000
'     7    00-00-00-00-01-00-00-00              4294967296
'    29    AA-AA-AA-AA-AA-AA-00-00         187649984473770
'    13    00-00-64-A7-B3-B6-E0-0D     1000000000000000000
'    35    00-00-E8-89-04-23-C7-8A    10000000000000000000
'    44    FF-FF-FF-FF-FF-FF-FF-7F     9223372036854775807
'    43    FF-FF-FF-FF-FF-FF-FF-FF    18446744073709551615

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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