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ToInt32 Method

BitConverter.ToInt32 Method

Returns a 32-bit signed integer converted from four 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 int ToInt32(
	byte[] value,
	int startIndex


Type: System.Byte[]

An array of bytes.

Type: System.Int32

The starting position within value.

Return Value

Type: System.Int32
A 32-bit signed integer formed by four bytes beginning at startIndex.


startIndex is greater than or equal to the length of value minus 3, and is less than or equal to the length of value minus 1.


value is null.


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

The ToInt32 method converts the bytes from index startIndex to startIndex + 3 to an Int32 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 BitConverter.

The following example uses the ToInt32 method to create Int32 values from a four-byte array and from the upper four bytes of an eight-byte array. It also uses the GetBytes(Int32) and ToInt32 methods to round-trip an Int32 value.

using System;

public class Example
   public static void Main()
      // Create an Integer from a 4-byte array.
      Byte[] bytes1 = { 0xEC, 0x00, 0x00, 0x00 };
      Console.WriteLine("{0}--> 0x{1:X4} ({1:N0})", FormatBytes(bytes1),
                                      BitConverter.ToInt32(bytes1, 0));
      // Create an Integer from the upper four bytes of a byte array.
      Byte[] bytes2 = BitConverter.GetBytes(Int64.MaxValue / 2);
      Console.WriteLine("{0}--> 0x{1:X4} ({1:N0})", FormatBytes(bytes2),
                                      BitConverter.ToInt32(bytes2, 4));

      // Round-trip an integer value. 
      int original = (int) Math.Pow(16, 3);
      Byte[] bytes3 = BitConverter.GetBytes(original);
      int restored = BitConverter.ToInt32(bytes3, 0);
      Console.WriteLine("0x{0:X4} ({0:N0}) --> {1} --> 0x{2:X4} ({2:N0})", original, 
                        FormatBytes(bytes3), restored);

   private static string FormatBytes(Byte[] bytes)
       string value = "";
       foreach (var byt in bytes)
          value += String.Format("{0:X2} ", byt);

       return value;
// The example displays the following output: 
//       EC 00 00 00 --> 0x00EC (236) 
//       FF FF FF FF FF FF FF 3F --> 0x3FFFFFFF (1,073,741,823) 
//       0x1000 (4,096) --> 00 10 00 00  --> 0x1000 (4,096)

.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
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