Timer组件。。抄的

Timer控件
  1using System;
  2using System.Web.UI;
  3using System.ComponentModel;
  4using System.Collections;
  5using System.Text;
  6
  7namespace PowerAsp.NET.Controls
  8{
  9    /**//// <summary>
 10    /// 书上抄的定时器例子。
 11    /// </summary>
 12    /// 
 13    
 14    public class WebTimer:Control,IPostBackEventHandler
 15    {
 16        public WebTimer()
 17        {
 18        }
 19        private member#region private member
 20        private int _interval = 5000;
 21        private bool _enabled = false;
 22        private static readonly object EventTimer = new object();
 23        #endregion
 24
 25        property#region property
 26        [Browsable(false)]
 27        public bool Visible
 28        {
 29            get
 30            {
 31                return base.Visible;
 32            }
 33            set
 34            {
 35                base.Visible = value;
 36            }
 37        }
 38
 39        [   DefaultValue(5000),
 40        Bindable(false),
 41        Description("每次刷新的间隔")
 42        ]
 43        public int Interval
 44        {
 45            get
 46            {
 47                return _interval;
 48            }
 49            set
 50            {
 51                _interval = value;
 52            }
 53        }
 54        [
 55        DefaultValue(false),
 56        Bindable(false),
 57        Description("Timer是否可用")
 58        ]
 59        public bool Enabled
 60        {
 61            get
 62            {
 63                return _enabled;
 64            }
 65            set
 66            {
 67                _enabled = value;
 68            }   
 69        }
 70        #endregion
 71
 72        events#region events
 73        public event EventHandler Timer
 74        {
 75            add
 76            {
 77                Events.AddHandler(EventTimer,value);
 78            }
 79            remove
 80            {
 81                Events.RemoveHandler(EventTimer,value);
 82            }
 83        }
 84        #endregion
 85
 86        event handler functions#region event handler functions
 87        protected virtual void OnTimer(EventArgs e)
 88        {
 89            EventHandler timerHandler = (EventHandler)Events[EventTimer];
 90            if(timerHandler != null)
 91            {
 92                timerHandler(this,e);
 93            }
 94        }
 95        #endregion
 96
 97        IPostBackEventHandler 成员#region IPostBackEventHandler 成员
 98
 99        void IPostBackEventHandler.RaisePostBackEvent(string eventArgument)
100        {
101            OnTimer(EventArgs.Empty);
102        }
103
104        #endregion
105
106        utility functions#region utility functions
107        private string buildJavaScript()
108        {
109            StringBuilder sb = new StringBuilder();
110            sb.Append("\n<script language=\"javascript\">\n<!--");
111            sb.AppendFormat("\n setTimeout(\"{0}\",{1});",new object[]{this.Page.GetPostBackEventReference(this),
112                                                                          _interval.ToString()
113                                                                      });
114            sb.Append("\n//-->\n</script>");
115            return sb.ToString();
116        }
117        #endregion
118
119        protected override void OnPreRender(EventArgs e)
120        {
121            base.OnPreRender (e);
122            Page.GetPostBackEventReference(this,"");
123        }
124
125
126        protected override void Render(HtmlTextWriter writer)
127        {
128            if(Page != null)
129            {
130                Page.VerifyRenderingInServerForm(this);
131            }
132            if(_enabled)
133                writer.Write(buildJavaScript());
134        }
135
136
137    }
138}