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C# - FileStream.Seek() Method | Random Access File

In this tutorial, we will learn how to access the file randomly using the Seek() method in C#?
Submitted by IncludeHelp, on November 17, 2017 [Last updated : March 27, 2023]

C# FileStream.Seek() Method

This is a method of "FileStream" class, it is used to set the current position file stream to given value.

Syntax

long Seek(long offset, SeekOrigin origin);

Parameter(s)

• Offset : move file stream to given value.
• Origin : It tells the origin, it may be start, current and end.

Example of accessing file randomly using Seek() Method in C#

using System;
using System.IO;

namespace ConsoleApplication1 {
  class Program {
    static void Main() {
      byte[] b1 = {10, 20, 24, 13, 15, 17};
      byte[] b2 = new byte[6];

      byte large = 0;
      FileStream f1;
      f1 = new FileStream("abc.txt", FileMode.Create, FileAccess.Write);

      f1.Write(b1, 0, 6);
      f1.Close();

      f1 = new FileStream("abc.txt", FileMode.Open, FileAccess.Read);

      f1.Seek(3, SeekOrigin.Begin);
      f1.Read(b2, 0, 3);

      large = b2[0];
      for (int i = 1; i < b2.Length; i++) {
        if (large < b2[i])
          large = b2[i];
      }

      Console.WriteLine("Largest Item is : " + large);
      f1.Close();
    }
  }
}

Output

Largest Item is : 17

Explanation

In this program, we are performing read and write operation into file and moving stream to 3^rd position from start and find largest element.

In above program, we need to remember, when we use "FileStream" class then we need to include System.IO namespace in the program.

C# FileStream Class Program »