Different methods for reading text file in C#

following are the different methods which we can use to read text file in C#:

  1. Read complete file into a string
  2. Read complete file into a string with Streams Reader
  3. Read all the lines from a file into an array
  4. Read a file line by line into string

Read complete file into a string

To read complete file into a single string we use ReadAllText method of System.IO.File class

private void GetContentInString()
    {
       string srtCompleteFileText = System.IO.File.ReadAllText(@"C:\test1.txt");
    }

Read complete file into a string with Streams Reader

To read a file with Stream Reader we will use System.IO.StreamReader class.

  public static string getFileAsString(string Full_fileName)
        {
            StreamReader strReader = null;
            string strcontents = null;
            try
            {
                FileStream flStream = new FileStream(Full_fileName, FileMode.Open, FileAccess.Read);
                strReader = new StreamReader(flStream);
                strcontents = strReader.ReadToEnd();
            }
            finally
            {
                if (strReader != null)
                {
                    strReader.Close();
                }
            }
            return strcontents;
        }

Read all the lines from a file into an array

We use ReadAllLines function of System.IO.File class to read all line of a file into single line array

private void GetContentInArray()
   {
       string[] All_lines = System.IO.File.ReadAllLines(@"C:\test12.txt");
   }

Read a file line by line into string

We use ReadLine function of System.IO.File class to read a file line by line.

using System;
using System.IO;
namespace ReadString
{
    class ReadAllLine
    {
        public static void Main(string[] args)
        {
            StreamReader sReader = new StreamReader("C:\text.txt");
            string my_line;
            while ((my_line = sReader.ReadLine()) != null)
            {
                Console.WriteLine("My_Line:" + my_line);
            }
            if (sReader != null)
            {
                sReader.Close();  //should be in a "finally" or "using" block
            }
        }
    }
}