C# 桌面时钟（透明窗体，定时提醒，开机启动）

【实例截图】

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace MyClock
{
    public partial class Alrms : Form
    {
        DateTime dt;
        MainForm mf;
        public Alrms(MainForm mf)
        {
            this.mf = mf;
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            dt = this.dateTimePicker1.Value;
            //MessageBox.Show(dt.Hour.ToString());
            //MessageBox.Show(DateTime.Now.Hour.ToString());
            //MessageBox.Show(dt.Minute.ToString());
            //MessageBox.Show(DateTime.Now.Minute.ToString());
            //MessageBox.Show(dt.Second.ToString());
            //MessageBox.Show(DateTime.Now.Second.ToString());
            //if (dt.Hour < DateTime.Now.Hour && dt.Minute < DateTime.Now.Minute &&
            //    dt.Second < DateTime.Now.Second)
            if (dt < DateTime.Now)
            {
                MessageBox.Show("对不起，您不能设置一个小于当前时间的值！");
                dateTimePicker1.Value = DateTime.Now;
                return;
            }
            if (infTextBox.Text == "")
            {
                MessageBox.Show("您必须设置一个提示信息！");
                return;
            }
            mf.Date = dt;
            mf.Inf = this.infTextBox.Text;
            mf.setEnable = true;
            MessageBox.Show("设置完毕！");
            this.Close();
        }

        private void Alrms_FormClosing(object sender, FormClosingEventArgs e)
        {
            mf.RemindToolStripMenuItem.Enabled = true;
        }
    }
}