[C#] How to use File.OpenWrite Method

The OpenWrite method opens a file for writing. If file does not exist, it creates a new file and opens if for writing. The OpenWrite method takes a file name as parameter and returns a FileStream object on the specified file.

FileStream fs = fi.OpenWrite();

Once we have a FileStream object, we can use its Write method to write to the file. The WriteMethod takes a byte array. The following code snippet creates a byte array and passes it to the Write method of the FileStream.

Byte[] info = new UTF8Encoding(true).GetBytes("New File using OpenWrite Method n");
fs.Write(info, 0, info.Length);

The following lists the complete code sample.

string fileName = @"C:\fileName.txt";
FileInfo fi = new FileInfo(fileName);
// If file does not exist, create file
if (!fi.Exists)
{
   //Create the file.
   using (FileStream fs = fi.Create())
   {
      Byte[] info = new UTF8Encoding(true).GetBytes("File Start");
      fs.Write(info, 0, info.Length);
   }
}
try
{
   // Open a file and add some contents to it
   using (FileStream fs = fi.OpenWrite())
   {
      Byte[] info = new UTF8Encoding(true).GetBytes("New File using OpenWrite Method n");
      fs.Write(info, 0, info.Length);
      info = new UTF8Encoding(true).GetBytes("----------START------------------------ n");
      fs.Write(info, 0, info.Length);
      info = new UTF8Encoding(true).GetBytes("Author: Mahesh Chand n");
      fs.Write(info, 0, info.Length);
      info = new UTF8Encoding(true).GetBytes("Book: ADO.NET Programming using C#n");
      fs.Write(info, 0, info.Length);
      info = new UTF8Encoding(true).GetBytes("----------END------------------------");
      fs.Write(info, 0, info.Length);
   }
   // Read file contents and display on the console
   using (FileStream fs = File.OpenRead(fileName))
   {
      byte[] byteArray = new byte[1024];
      UTF8Encoding fileContent = new UTF8Encoding(true);
      while (fs.Read(byteArray, 0, byteArray.Length) > 0)
      {
         Console.WriteLine(fileContent.GetString(byteArray));
      }
   }
}
catch (Exception Ex)
{
   Console.WriteLine(Ex.ToString());
}

NOTE:
A File must be opened using an IO resource before it can be read or write to. A file can be opened to read and/or write purpose. The FileInfo class provides four methods to open a file.

Xem thêm  [C#] How to Append a File in C#

+ Open
+ OpenRead
+ OpenText
+ OpenWrite

You may also like...

2 Responses

  1. hgf says:

    Your way of telling everything in this post is really nice, all can simply be aware of it, Thanks a
    lot.

  1. 03/03/2019

    […] [C#] How to use File.OpenWrite Method […]

Leave a Reply

Your email address will not be published. Required fields are marked *