In this tutorial I will show you how to use C# to connect to a FTP server and perform basic operations:

  • uploading a file
  • downloading a file
  • deleting a file

1.Connecting & Logging In

Before doing operations on files, you must learn how to connect to the FTP server. For every action, you have to use a FtpWebRequest - and with it, you tell the server what to do. When the FtpWebRequest is created, you have to provide the path to the file:

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FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create("ftp://myFtpAddress.tld/myFile.txt");
// 'ftp://myFtpAddress.tld/myFile.txt' is the path to the file

Now, we have to provide the authentication data (username & password). This data must be included into the FTP request:

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ftpRequest.Credentials = new NetworkCredential("username", "password");

This is how your code should look like:

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FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create("ftp://myFtpAddress.tld/myFile.txt");

ftpRequest.Credentials = new NetworkCredential("username", "password");

After this, you can start doing operations with files.

2.Uploading a file

You have to tell the FTP Server what you want to do - in this case, you want to upload a file. So, you’ll set the WebRequestMethod to UploadFile:

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ftpRequest.Method = WebRequestMethods.Ftp.UploadFile;

The line above tells the server that you want to upload a file - so it’ll wait for file’s content. The file’s content must be sent as a byte array (byte[]):

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byte[] fileContent;  //in this array you'll store the file's content

using (StreamReader sr = new StreamReader("myFile.txt"))  //'myFile.txt' is the file we want to upload
{
       fileContent = Encoding.UTF8.GetBytes(sr.ReadToEnd()); //getting the file's content, already transformed into a byte array
}

using (Stream sw = ftpRequest.GetRequestStream())
{
       sw.Write(fileContent, 0, fileContent.Length);  //sending the content to the FTP Server
}

The complete code for file upload will look like this:

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using System;
using System.Net;
using System.IO;
using System.Text;

namespace testProj
{
    class Program
    {
        static void Main(string[] args)
        {
            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create("ftp://myFtpAddress.tld/myFile.txt");

            ftpRequest.Credentials = new NetworkCredential("username", "password");
            ftpRequest.Method = WebRequestMethods.Ftp.UploadFile;

            byte[] fileContent;

            using (StreamReader sr = new StreamReader("myFile.txt"))
            {
                fileContent = Encoding.UTF8.GetBytes(sr.ReadToEnd()); 
            }

            using (Stream sw = ftpRequest.GetRequestStream())
            {
                sw.Write(fileContent, 0, fileContent.Length);
            }

            ftpRequest.GetResponse();
        }
    }
}

3.Downloading a file

This is easier, this time the server will send to our program the file’s content. But first, we must tell the server that we want to download a file:

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ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;

Then, we’ll get the server’s response - that’s the file we want. To do this, you can use a StreamReader to read from the main Stream.

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using (Stream sw = ftpRequest.GetResponse().GetResponseStream())  //getting the response stream
{
      StreamReader sr = new StreamReader(sw);   //reading from the stream
      Console.WriteLine(sr.ReadToEnd());   //showing the file's content
}

And the complete code:

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using System;
using System.Net;
using System.IO;
using System.Text;

namespace testProj
{
    class Program
    {
        static void Main(string[] args)
        {
            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create("ftp://myFtpAddress.tld/myFile.txt");

            ftpRequest.Credentials = new NetworkCredential("username", "password");
            ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;

            using (Stream sw = ftpRequest.GetResponse().GetResponseStream())
            {
                StreamReader sr = new StreamReader(sw);
                Console.WriteLine(sr.ReadToEnd());
            }
        }
    }
}

4.Deleting a file

Once again, tell the server what you want to do (delete a file), using WebRequestMethods:

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ftpRequest.Method = WebRequestMethods.Ftp.DeleteFile;

And that’s all ! - no additional code is required to do this.
The complete source code:

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using System;
using System.Net;
using System.IO;
using System.Text;

namespace testProj
{
    class Program
    {
        static void Main(string[] args)
        {
            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create("ftp://myFtpAddress.tld/myFile.txt");

            ftpRequest.Credentials = new NetworkCredential("username", "password");
            ftpRequest.Method = WebRequestMethods.Ftp.DeleteFile;

            ftpRequest.GetResponse();  
        }
    }
}