ASP.NET Session 8

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ASP.NET Session 8

  1. 1. Application on File Program Session 8
  2. 2. Objectives  Typically example of file read & write  Simple File Handling Program  Several Home work
  3. 3. Typical example of file read & write try { FileStream aFile = new FileStream("Log.txt", FileMode.OpenOrCreate); StreamWriter sw = new StreamWriter(aFile); bool truth = true // Write data to file. sw.WriteLine("Hello to you."); sw.WriteLine("It is now {0} and things are looking good.“,DateTime.Now.ToLongDateString());
  4. 4. sw.Write("More than that,"); sw.Write(" it’s {0} that C# is fun.", truth); sw.Close(); } catch (IOException ee) { Console.WriteLine("An IO exception has been thrown!"); Console.WriteLine(ee.ToString()); Console.ReadLine(); return; }
  5. 5. • Go to the application directory and find the Log.txt file. It is located in the binDebug folder because you used a relative path. • The WriteLine() method writes the string passed to it, followed immediately by a newline character. • You can see in the example that this causes the next write operation to begin on a new line. • The Write() method simply writes the string passed to it to the file, without a newline character appended. • Two sentence is in one line.
  6. 6. The StreamReader Object • try • { • FileStream aFile = new FileStream("Log.txt", FileMode.Open); • StreamReader sr = new StreamReader(aFile); • line = sr.ReadLine(); • // Read data in line by line. • while(line != null) • { • Console.WriteLine(line); • line = sr.ReadLine(); • } • sr.Close(); • }
  7. 7. • catch(IOException e) • { • Console.WriteLine("An IO exception has been thrown!"); • Console.WriteLine(e.ToString()); • return; • } • Console.ReadKey();  ReadLine() method to read text from the file.  This method reads text until a new line is found,and returns the resulting text as a string.  The method returns a null when the end of the file has been reached, which you use to test for the end of the file.
  8. 8.  Note that you use a while loop, which ensures that the line read isn’t null before any code in the body of the loop is executed. Simple File Handling Program String line,k=""; StreamReader sr = new StreamReader("E:trainingreadsample.txt"); StreamWriter sw = new StreamWriter("E:trainingWritesample.txt"); line = sr.ReadLine();
  9. 9. while (line != null) { k += line; line = sr.ReadLine(); } sw.WriteLine(k); sw.Close(); sr.Dispose(); Direct using streamReader & streamWriter
  10. 10. Input : readsample.txt Contain • welcome TO .NET WORLD. • Asp.Net IS Microsoft Own Product. • File handling is done by Streamreader & streamwriter • Simple program about File. • OutPut: • Writesample.txt Contain • welcome TO .NET WORLD.Asp.Net IS Microsoft Own Product.File handling is done by Streamreader & streamwriter .Simple program about File.
  11. 11. Tasks(to be done in the class session): • 1)Print first 5 characters from a file in a single line. • 2)Print number of each line. • 3)Create two files where 1st file will contain 1st &3rd lines and the other file will contain 2nd &4th lines.

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