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BitConverter.ToUInt64 Method

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 static ulong ToUInt64(
	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.UInt64
A 64-bit unsigned integer formed by the 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 UInt64 values with the ToUInt64 method.


// Example of the BitConverter.ToUInt64 method.
using System;

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

   // Convert eight byte array elements to a ulong and display it.
   public static void BAToUInt64(System.Windows.Controls.TextBlock outputBlock, byte[] bytes, int index)
   {
      ulong value = BitConverter.ToUInt64(bytes, index);

      outputBlock.Text += String.Format(formatter, index,
          BitConverter.ToString(bytes, index, 8), value) + "\n";
   }

   // Display a byte array, using multiple lines if necessary.
   public static void WriteMultiLineByteArray(System.Windows.Controls.TextBlock outputBlock, byte[] bytes)
   {
      const int rowSize = 20;
      int iter;

      outputBlock.Text += "initial byte array" + "\n";
      outputBlock.Text += "------------------" + "\n";

      for (iter = 0; iter < bytes.Length - rowSize; iter += rowSize)
      {
         outputBlock.Text += String.Format(
             BitConverter.ToString(bytes, iter, rowSize));
         outputBlock.Text += "-" + "\n";
      }

      outputBlock.Text += String.Format(BitConverter.ToString(bytes, iter)) + "\n";
      outputBlock.Text += "\n";
   }

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      byte[] byteArray = {
            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 };

      outputBlock.Text += String.Format(
          "This example of the BitConverter.ToUInt64( byte[ ], " +
          "int ) \nmethod generates the following output. It " +
          "converts elements \nof a byte array to ulong values.\n") + "\n";

      WriteMultiLineByteArray(outputBlock, byteArray);

      outputBlock.Text += String.Format(formatter, "index", "array elements",
          "ulong") + "\n";
      outputBlock.Text += String.Format(formatter, "-----", "--------------",
          "------") + "\n";

      // Convert byte array elements to ulong values.
      BAToUInt64(outputBlock, byteArray, 3);
      BAToUInt64(outputBlock, byteArray, 0);
      BAToUInt64(outputBlock, byteArray, 21);
      BAToUInt64(outputBlock, byteArray, 7);
      BAToUInt64(outputBlock, byteArray, 29);
      BAToUInt64(outputBlock, byteArray, 13);
      BAToUInt64(outputBlock, byteArray, 35);
      BAToUInt64(outputBlock, byteArray, 44);
      BAToUInt64(outputBlock, byteArray, 43);
   }
}

/*
This example of the BitConverter.ToUInt64( byte[ ], int )
method generates the following output. It converts elements
of a byte array to ulong 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                   ulong
-----             --------------                  ------
    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
*/


Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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