BitConverter.ToInt32 Method

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Overloads

ToInt32(ReadOnlySpan<Byte>)	Converts a read-only byte span into a 32-bit signed integer.
ToInt32(Byte[], Int32)	Returns a 32-bit signed integer converted from four bytes at a specified position in a byte array.

ToInt32(ReadOnlySpan<Byte>)

Source:

BitConverter.cs

Converts a read-only byte span into a 32-bit signed integer.

public:
 static int ToInt32(ReadOnlySpan<System::Byte> value);

public static int ToInt32 (ReadOnlySpan<byte> value);

static member ToInt32 : ReadOnlySpan<byte> -> int

Public Shared Function ToInt32 (value As ReadOnlySpan(Of Byte)) As Integer

Parameters

value

ReadOnlySpan<Byte>

A read-only span containing the bytes to convert.

Returns

Int32

A 32-bit signed integer representing the converted bytes.

Exceptions

ArgumentOutOfRangeException

The length of value is less than 4.

ToInt32(Byte[], Int32)

Source:

BitConverter.cs

Returns a 32-bit signed integer converted from four bytes at a specified position in a byte array.

public:
 static int ToInt32(cli::array <System::Byte> ^ value, int startIndex);

public static int ToInt32 (byte[] value, int startIndex);

static member ToInt32 : byte[] * int -> int

Public Shared Function ToInt32 (value As Byte(), startIndex As Integer) As Integer

Parameters

value

Byte[]

An array of bytes that includes the four bytes to convert.

startIndex

Int32

The starting position within value.

Returns

Int32

A 32-bit signed integer formed by four bytes beginning at startIndex.

Exceptions

ArgumentException

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.

ArgumentNullException

value is null.

ArgumentOutOfRangeException

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

Examples

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)

open System

let formatBytes (bytes: byte []) =
    bytes
    |> Array.map (fun x -> $"{x:X2}")
    |> String.concat ""

// Create an Integer from a 4-byte array.
let bytes1 = [| 0xECuy; 0x00uy; 0x00uy; 0x00uy |]
let int1  = BitConverter.ToInt32(bytes1, 0)
printfn $"{formatBytes bytes1}--> 0x{int1:X4} ({int1:N0})"

// Create an Integer from the upper four bytes of a byte array.
let bytes2 = BitConverter.GetBytes(Int64.MaxValue / 2L)
let int2 = BitConverter.ToInt32(bytes2, 4)
printfn $"{formatBytes bytes2}--> 0x{int2:X4} ({int2:N0})"

// Round-trip an integer value.
let original = pown 16 3
let bytes3 = BitConverter.GetBytes original
let restored = BitConverter.ToInt32(bytes3, 0)
printfn $"0x{original:X4} ({original:N0}) --> {formatBytes bytes3} --> 0x{restored:X4} ({restored:N0})"


// 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)

Module Example
   Public Sub Main()
      ' Create an Integer from a 4-byte array.
      Dim bytes1() As Byte = { &hEC, &h00, &h00, &h00 }
      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.
      Dim bytes2() As Byte = BitConverter.GetBytes(Int64.MaxValue \ 2)
      Console.WriteLine("{0}--> 0x{1:X4} ({1:N0})", FormatBytes(bytes2),
                                      BitConverter.ToInt32(bytes2, 4))
      
      ' Round-trip an integer value.
      Dim original As Integer = CInt(16^3)
      Dim bytes3() As Byte = BitConverter.GetBytes(original)
      Dim restored As Integer = BitConverter.ToInt32(bytes3, 0)
      Console.WriteLine("0x{0:X4} ({0:N0}) --> {1} --> 0x{2:X4} ({2:N0})", original, 
                        FormatBytes(bytes3), restored)
   End Sub
   
   Private Function FormatBytes(bytes() As Byte) As String
       Dim value As String = ""
       For Each byt In bytes
          value += String.Format("{0:X2} ", byt)
       Next
       Return value
   End Function
End Module
' 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)

Remarks

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.

See also

• GetBytes(Int32)