Stream file, file in use, FileSystemWatcher and question about threads

I've been trying to create a script which takes the content of a text file which may look like this (1 line text in a .txt. file):

SomeData     SomeData     SomeData

and these files are dropped randomly into a folder. Sometimes in 10's, sometimes 1 at a time. The files are then moved from the folder using robocopy to another folder roughly every ten mins.

Anyway, I wanted to read each file's single line of text and insert into the database.

Works fine once or twice, but then I get file is in use error.

Tried switching from File.ReadAllText(textFile) to FileStream and still have the same problem.

Can anyone help?

Also, I'm a little worried about the number of threads this may use when dropped onto a server. I can see the threads in Visual Studio Code, but interested to know what I could do to improve my script and make it more efficient?

I am new to coding! This will be my first.

using System;
using System.IO;
using System.Data.SqlClient;


namespace IDGFileSystemWatcher
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = "C:/Test/";
            MonitorDirectory(path);
            Console.ReadKey();
        }

        private static void MonitorDirectory(string path)
        {
            FileSystemWatcher fileSystemWatcher = new FileSystemWatcher();
            fileSystemWatcher.Path = path;
            fileSystemWatcher.Created += FileSystemWatcher_Created;
            fileSystemWatcher.EnableRaisingEvents = true;
        }

        private static void FileSystemWatcher_Created(object sender, FileSystemEventArgs e)
        {
            string txtContents;
            string dir = "C:/Test/";
            string textFile = dir + e.Name;
            //string text = File.ReadAllText(textFile);

            FileStream fs = new FileStream(textFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            StreamReader sr = new StreamReader(fs);
            txtContents = sr.ReadToEnd();
            sr.Close();

            string[] splitstring = txtContents.Split(new char[0], StringSplitOptions.RemoveEmptyEntries);
            DateTime now = DateTime.Now;
                 
            SqlConnection connection = new SqlConnection();
            connection.ConnectionString =
                        "Data Source=computername;" +
                        "Initial Catalog=contents;" +
                        "User id=userid;" + 
                        "Password=password;";
                    
            string query = "INSERT INTO dbo.MB1B (Field1, Field2, Field3, TStamp) VALUES (@Field1, @Field2, @Field3, @TStamp)";

            using (SqlCommand command = new SqlCommand(query, connection))
            {
                command.Parameters.AddWithValue("@Field1", splitstring[0]);
                command.Parameters.AddWithValue("@Field2", splitstring[1]);
                command.Parameters.AddWithValue("@Field3", splitstring[2]);
                command.Parameters.AddWithValue("@TStamp", now);

                connection.Open();
                int result = command.ExecuteNonQuery();

                // Check Error
                if (result < 0) 
                {
                    Console.WriteLine("Error inserting data into database!");
                }

                // connection.Close();
            }
        }
    }
}

I tried using both File.ReadAllText(textFile) and FileStream.

I have tried to check if the files are in use but I am just copying and pasting test /txt files from one folder to another sometimes in 10's and sometimes in singles. Or dropping 50 test text files into a folder.

I've tried waiting for usage to time out (so the file isn't in use) and I have tried adding a pause to the script.

Please note that nothing is being written back to the file, I am simply reading a file and entering three items from the single line of text in the file to the database.