C#使用timer实现的简单闹钟程序

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Threading;
using System.Timers;
using System.IO;
using System.Reflection;
namespace timerAlarm
{
  public class TimerForm : System.Windows.Forms.Form
  {
    //Controls and Components
    private System.Windows.Forms.TextBox timerInput;
    private System.Windows.Forms.Button StartButton;
    private System.Windows.Forms.Button ResetButton;
    private System.ComponentModel.IContainer components;
    //Timer and associated variables
    private System.Timers.Timer timerClock = new System.Timers.Timer();
    private int clockTime = 0;
    private int alarmTime = 0;
    public TimerForm()
    {
      InitializeComponent();
      InitializeTimer();
    }
    protected override void Dispose( bool disposing )
    {
      if( disposing )
      {
        if (components != null)
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }
    #region Windows Form Designer generated code
    /// <SUMMARY>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </SUMMARY>
    private void InitializeComponent()
    {
      this.components = new System.ComponentModel.Container();
      System.Resources.ResourceManager resources = new System.
        Resources.ResourceManager(typeof(TimerForm));
      this.timerInput = new System.Windows.Forms.TextBox();
      this.StartButton = new System.Windows.Forms.Button();
      this.ResetButton = new System.Windows.Forms.Button();
      this.SuspendLayout();
      //
      // timerInput
      //
      this.timerInput.Location = new System.Drawing.Point(12, 13);
      this.timerInput.Name = "timerInput";
      this.timerInput.Size = new System.Drawing.Size(50, 20);
      this.timerInput.TabIndex = 0;
      this.timerInput.Text = "00:00:00";
      //
      // StartButton
      //
      this.StartButton.FlatStyle = System.Windows.Forms.
        FlatStyle.System;
      this.StartButton.Location = new System.Drawing.Point(75, 11);
      this.StartButton.Name = "StartButton";
      this.StartButton.TabIndex = 1;
      this.StartButton.Text = "Start";
      this.StartButton.Click += new System.EventHandler
        (this.StartButton_Click);
      //
      // ResetButton
      //
      this.ResetButton.FlatStyle = System.Windows.Forms.
        FlatStyle.System;
      this.ResetButton.Location = new System.Drawing.Point(161, 11);
      this.ResetButton.Name = "ResetButton";
      this.ResetButton.TabIndex = 2;
      this.ResetButton.Text = "Reset";
      this.ResetButton.Click += new
        System.EventHandler(this.ResetButton_Click);
      //
      // TimerForm
      //
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(247, 46);
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
         this.ResetButton,
         this.StartButton,
         this.timerInput});
      this.FormBorderStyle = System.Windows.Forms.
        FormBorderStyle.FixedSingle;
      this.Icon = ((System.Drawing.Icon)(resources.
        GetObject("$this.Icon")));
      this.MaximizeBox = false;
      this.Name = "TimerForm";
      this.StartPosition = System.Windows.Forms.
        FormStartPosition.CenterScreen;
      this.Text = "Alarm Timer";
      this.Resize += new System.EventHandler(this.
        TimerForm_Resized);
      this.ResumeLayout(false);
    }
    #endregion
    public void InitializeTimer()
    {
      this.timerClock.Elapsed += new ElapsedEventHandler(OnTimer);
      this.timerClock.Interval = 1000;
      this.timerClock.Enabled = true;
    }
    [STAThread]
    static void Main()
    {
      Application.Run(new TimerForm());
    }
    private void TimerForm_Resized(object sender, System.EventArgs e)
    {
      if( this.WindowState == FormWindowState.Minimized )
      {
        this.Hide();
      }
    }
    private void StartButton_Click(object sender, System.EventArgs e)
    {
      this.clockTime = 0;
      inputToSeconds( this.timerInput.Text );
    }
    private void ResetButton_Click(object sender, System.EventArgs e)
    {
      try
      {
        this.clockTime = 0;
        this.alarmTime = 0;
        this.timerInput.Text = "00:00:00";
      }
      catch( Exception ex )
      {
        MessageBox.Show("ResetButton_Click(): " + ex.Message );
      }
    }
    public void OnTimer(Object source, ElapsedEventArgs e)
    {
      try
      {
        this.clockTime++;
        int countdown = this.alarmTime - this.clockTime ;
        if( this.alarmTime != 0 )
        {
          this.timerInput.Text = secondsToTime(countdown);
        }
        //Sound Alarm
        if( this.clockTime == this.alarmTime )
        {
          MessageBox.Show("Play Sound");
        }
      }
      catch( Exception ex )
      {
        MessageBox.Show("OnTimer(): " + ex.Message );
      }    
    }
    private void inputToSeconds( string timerInput )
    {
      try
      {
        string[] timeArray = new string[3];
        int minutes = 0;
        int hours = 0;
        int seconds = 0;
        int occurence = 0;
        int length = 0;
        occurence = timerInput.LastIndexOf(":");
        length = timerInput.Length;
        //Check for invalid input
        if( occurence == -1 || length != 8 )
        {
          MessageBox.Show("Invalid Time Format.");
          ResetButton_Click( null, null );
        }
        else
        {
          timeArray = timerInput.Split(':');
          seconds = Convert.ToInt32( timeArray[2] );
          minutes = Convert.ToInt32( timeArray[1] );
          hours = Convert.ToInt32( timeArray[0] );
          this.alarmTime += seconds;
          this.alarmTime += minutes*60;
          this.alarmTime += (hours*60)*60;
        }
      }
      catch( Exception e )
      {
        MessageBox.Show("inputToSeconds(): " + e.Message );
      }
    }
    public string secondsToTime( int seconds )
    {
      int minutes = 0;
      int hours = 0;
      while( seconds >= 60 )
      {
        minutes += 1;
        seconds -= 60;
      }
      while( minutes >= 60 )
      {
        hours += 1;
        minutes -= 60;
      }
      string strHours = hours.ToString();
      string strMinutes = minutes.ToString();
      string strSeconds = seconds.ToString();
      if( strHours.Length < 2 )
        strHours = "0" + strHours;
      if( strMinutes.Length < 2 )
        strMinutes = "0" + strMinutes;
      if( strSeconds.Length < 2 )
        strSeconds = "0" + strSeconds;
      return strHours + ":" + strMinutes + ":" + strSeconds;
    }
  }
}