AntiRemoveFile.cs

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

static class AntiRemove
{
    const uint GENERIC_READ = 0x80000000;
    const uint DUPLICATE_SAME_ACCESS = 0x00000002;
    const uint FILE_SHARE_READ = 1;
    const uint OPEN_EXISTING = 3;

    public static bool LockFile(string filePath, params string[] processes)
    {
        IntPtr hCurrentProcess;
        using (Process current = Process.GetCurrentProcess())
        {
            hCurrentProcess = current.Handle;
        }

        IntPtr hFile = CreateFile(filePath, GENERIC_READ, FILE_SHARE_READ, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);

        if (hFile == IntPtr.Zero)
            return false;

        int count = 0;

        foreach (Process p in Process.GetProcesses())
        {
            using (p)
            {
                try
                {
                    if (processes.Length == 0 || Array.IndexOf(processes, p.ProcessName.ToLowerInvariant()) != -1)
                    {
                        Console.WriteLine("Locking with " + p);
                        IntPtr hFileClone;
                        IntPtr hProcess = p.Handle;
                        if (!DuplicateHandle(((IntPtr)(-1)), hFile, hProcess, out hFileClone, GENERIC_READ, false, DUPLICATE_SAME_ACCESS))
                        {
                            Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
                        }
                        count++;
                    }
                }
                catch
                {
                    Console.WriteLine("Failed locking with " + p);
                }
            }
        }

        CloseHandle(hFile);

        return count > 0;
    }

    [DllImport("kernel32", SetLastError = true)]
    static extern bool CloseHandle(IntPtr hObject);

    [DllImport("kernel32", SetLastError = true)]
    static extern bool DuplicateHandle(IntPtr hSourceProcessHandle, IntPtr hSourceHandle, IntPtr hTargetProcessHandle, out IntPtr lpTargetHandle, uint dwDesiredAccess, bool bInheritHandle, uint dwOptions);

    [DllImport("kernel32", SetLastError = true)]
    static extern IntPtr CreateFile(string lpFileName, uint dwDesiredAccess,
    uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition,
    uint dwFlagsAndAttributes, IntPtr hTemplateFile);
}