NextBytes Method
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Random.NextBytes Method (Byte[])


Fills the elements of a specified array of bytes with random numbers.

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

public virtual void NextBytes(
	byte[] buffer


Type: System.Byte[]

An array of bytes to contain random numbers.

Exception Condition

buffer is null.

Each element of the array of bytes is set to a random number greater than or equal to 0, and less than or equal to MaxValue.

For example, to generate a cryptographically secured random number suitable for creating a random password, use a method such as RNGCryptoServiceProvider.GetBytes.

Notes to Inheritors:

Starting with the .NET Framework version 2.0, if you derive a class from Random and override the Sample method, the distribution provided by the derived class implementation of the Sample method is not used in calls to the base class implementation of the NextBytes method. Instead, the uniform distribution returned by the base Random class is used. This behavior improves the overall performance of the Random class. To modify this behavior to call the Sample method in the derived class, you must also override the NextBytes method.

The following example demonstrates how to use the NextBytes method to fill an array of bytes with random byte values.

using System;

public class Example 
    public static void Main() 
        Random rnd = new Random();
        Byte[] b = new Byte[10];
        Console.WriteLine("The Random bytes are: ");
        for (int i = 0; i <= b.GetUpperBound(0); i++) 
            Console.WriteLine("{0}: {1}", i, b[i]);  
// The example displays output similar to the following:
//       The Random bytes are:
//       0: 131
//       1: 96
//       2: 226
//       3: 213
//       4: 176
//       5: 208
//       6: 99
//       7: 89
//       8: 226
//       9: 194

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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