using System;

using Microsoft.SharePoint.Client;

​

public class Program

{

    public static void Main()

    {   

        UploadDocument("http://tenant.sharepoint.com/sites/Files/", "FTP", "FTP", "Document Title", /*BYTESTREAM*/);

    }

    public void UploadDocument(string siteURL, string documentListName, string documentListURL, string documentName, byte[] documentStream)

    {

        using (ClientContext clientContext = new ClientContext(siteURL))

        {

            //Get Document List

            List documentsList = clientContext.Web.Lists.GetByTitle(documentListName);

​

            var fileCreationInformation = new FileCreationInformation();

            //Assign to content byte[] i.e. documentStream

​

            fileCreationInformation.Content = documentStream;

            //Allow owerwrite of document

​

            fileCreationInformation.Overwrite = true;

            //Upload URL

​

            fileCreationInformation.Url = siteURL + documentListURL + documentName;

            Microsoft.SharePoint.Client.File uploadFile = documentsList.RootFolder.Files.Add(

                fileCreationInformation);

​

            //Update the metadata for a field having name "DocType"

            //uploadFile.ListItemAllFields["DocType"] = "Favourites";

​

            uploadFile.ListItemAllFields.Update();

            clientContext.ExecuteQuery();

        }

    }

}