ICallbackEventHandler实现的无刷新翻页组件

转载 于 2010-06-09 09:00:00 发布 · 531 阅读 · 0
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#string #javascript #null #object #exception #div

本文介绍了一个基于ASP.NET的Ajax分页控件实现细节，包括控件的构造、属性设置、视图状态维护及回调事件处理等。通过具体代码展示了如何在网页中使用该控件进行数据分页。

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01.[DefaultProperty("TotalRecord"),

02.    ToolboxData("<{0}:AjaxPager runat=server></{0}:AjaxPager>")]
03.    public class AjaxPager : WebControl,ICallbackEventHandler
04.    {
05.        public AjaxPager()
06.            : base(HtmlTextWriterTag.Div)
07.        {
08.            this.Load += new EventHandler(AjaxPager_Load);
09.        }
10.        void AjaxPager_Load(object sender, EventArgs e)
11.        {
12.            string script = "function AjaxPagerCallBack(returnData){var parts =returnData.split('[_]'); document.getElementById('" + this.UniqueID.Replace ('$','_') + "').innerHTML = parts[0];document.getElementById('" + Info.ContainID + "').innerHTML=parts[1]}";
13.            this.Page.ClientScript.RegisterClientScriptBlock(this.Page.GetType(), "AjaxPagerCallBack", script, true);
14.        }
15.}

这里在Load事件里向页面注册了一段JS，AjaxPagerCallBack方法做两个操作，把自己表现的数据放入自己在客户端生成的DIV容器里，即id为this.UniqueID.Replace('$','_')的div,ClientID好像也可以！哈，一时糊涂！第二步就是把分页数据放到id为Info.ContainID的div中，Info对象下面会说到。

变量属性

01.#region 变量
02.        private string _BarBackGroundColor = "#FFFFFF";
03.        private string _BarLinkColor = "Navy";
04.        private string _BarCurrentColor = "#EEEEEE";
05.        private int _TotalRecord = 50;
06.        private int _TotalPage = 0;
07.        private int _CurrentIndex = 1;
08.        private int _ItemSize = 10;
09.        private PageInfo _Info=new PageInfo ();
10.          
11.        #endregion
12.        #region 属性
13.        #region 外观
14.        [Description("分页背景色"),
15.        Bindable(true),
16.        Category("外观"),
17.        DefaultValue("#FFFFFF")]
18.        public string BarBackGroundColor
19.        {
20.            get { return _BarBackGroundColor; }
21.            set { _BarBackGroundColor = value; }
22.        }
23.        [Description("分页条链接数字颜色"),
24.        Bindable(true),
25.        Category("外观"),
26.        DefaultValue("Navy")]
27.        public string BarLinkColor
28.        {
29.            get { return _BarLinkColor; }
30.            set { _BarLinkColor = value; }
31.        }
32.        [Description("分页条当前页数字颜色"),
33.        Bindable(true),
34.        Category("外观"),
35.        DefaultValue("#EEEEEE")]
36.        public string BarCurrentColor
37.        {
38.            get { return _BarCurrentColor; }
39.            set { _BarCurrentColor = value; }
40.        }
41.        #endregion
42.        #region 行为
43.        [Description("总记录数"),
44.        Category("行为"),
45.        DefaultValue(50)]
46.        public int TotalRecord
47.        {
48.            get { return _TotalRecord; }
49.            set
50.            {
51.                _TotalRecord = value;
52.            }
53.        }
54.        [Description("总页数"),
55.        Category("行为"),
56.        DefaultValue(0)]
57.        public int TotalPage
58.        {
59.            get { return _TotalPage; }
60.        }
61.        [Description("Bar的大小"),
62.        Category("行为"),
63.        DefaultValue(10)]
64.        public int BarSize
65.        {
66.            get { return _ItemSize; }
67.            set
68.            {
69.                foreach (char c in System.Convert.ToString(value))
70.                {
71.                    if (!Char.IsNumber(c))
72.                    {
73.                        _ItemSize = 10;
74.                        break;
75.                    }
76.                }
77.                _ItemSize = value;
78.            }
79.        }
80.        [Description("当前页值"),
81.        Category("行为"),
82.        DefaultValue(1)]
83.        public int PageIndex
84.        {
85.            get { return _CurrentIndex; }
86.            set { _CurrentIndex = value; }
87.        }
88.        #endregion
89.        public PageInfo Info
90.        {
91.            get { return _Info; }
92.            set { _Info = value; }
93.        }
94.        #endregion
这里自不必细说。其中的PageInfo如下：
PageInfo
01.[Serializable]
02.    public class PageInfo
03.    {
04.        private string _RepeaterUniqueID;
05.        private string _ContainID="AjaxData";
06.        private string _TableName = string.Empty;
07.        private string _IdentityField = "ID";
08.        private int _PageSize = 10;
09.        private string _Fields = "*";
10.        private bool _IsDesc = true;
11.        private string _Content = string.Empty;
12.        private string _ConnectStringName = string.Empty;
13.        public string RepeaterUniqueID
14.        {
15.            get { return _RepeaterUniqueID; }
16.            set { _RepeaterUniqueID = value; }
17.        }
18.        public string ContainID
19.        {
20.            get { return _ContainID; }
21.            set { _ContainID = value; }
22.        }
23.        public int PageSize
24.        {
25.            get { return _PageSize; }
26.            set
27.            {
28.                _PageSize = int.Parse(value.ToString());
29.            }
30.        }
31.        public string TableName
32.        {
33.            get { return _TableName; }
34.            set { _TableName = value; }
35.        }
36.        public string IdentityField
37.        {
38.            get { return _IdentityField; }
39.            set { _IdentityField = value; }
40.        }
41.        public string Fields
42.        {
43.            get { return _Fields; }
44.            set { _Fields = value; }
45.        }
46.        public bool IsDesc
47.        {
48.            get { return _IsDesc; }
49.            set { _IsDesc = value; }
50.        }
51.        public string Content
52.        {
53.            get { return _Content; }
54.            set { _Content = value; }
55.        }
56.        public string ConnectStringName
57.        {
58.            get { return _ConnectStringName; }
59.            set { _ConnectStringName = value; }
60.        }
61.    }
这是标记为Serializable，是因为下面要保存到ViewState里。

辅助方法
01.private string GetContents()
02.        {
03.            this._TotalPage = ((this.TotalRecord / this.Info.PageSize) * this.Info.PageSize == this.TotalRecord) ? (this.TotalRecord / this.Info.PageSize) : ((this.TotalRecord / this.Info.PageSize) + 1);
04.            int BeginRecord = (this.PageIndex - 1) * this.Info.PageSize + 1;
05.            int EndRecord = Math.Min(this.PageIndex * this.Info.PageSize, this.TotalRecord);
06.            string PageInfo = string.Format("[每页<span style='color:#CC0000'>{0}({1}-{2})</span>条&nbsp;&nbsp;共<span style='color:#CC0000'>{3}</span>条<span style='color:#CC0000'>{4}</span>页]", Info.PageSize, BeginRecord, EndRecord, this.TotalRecord, this.TotalPage);
07.            StringBuilder PageListStr = new StringBuilder();
08.            string PageIndexColor = "#000000";
09.            int SingleNumber = this.TotalPage - (TotalPage / BarSize) * BarSize;
10.            int IntPageForMax = (this.PageIndex - 1) / BarSize;
11.            int MinInt = (1 + BarSize * IntPageForMax);
12.            int MaxInt = ((IntPageForMax + 1) * BarSize) > TotalPage ? TotalPage : ((IntPageForMax + 1) * BarSize);
13.            if (this.TotalRecord == 0 || this.TotalPage == 0)
14.            {
15.                PageListStr.AppendFormat("<span style='color:'{0};margin:auto 3px;'>0</span>", PageIndexColor);
16.                PageListStr.AppendFormat(" [共<span style='color:#CC0000'>0</span>页/当前第<span style='color:#CC0000'>0</span>页   共<span style='color:#CC0000'>0</span>条记录,当前记录数<span style='color:#CC0000'>0</span>到<span style='color:#CC0000'>0</span>]");
17.                return PageListStr.ToString();
18.            }
19.            else
20.            {
21.                if (this.TotalPage <= this.BarSize)
22.                { 
23.                    for (int i = 1; i <= TotalPage; i++)
24.                    {
25.                        PageIndexColor = PageIndex == i ? "#CC0000" : "#000000";
26.                        if (PageIndex == i)
27.                            PageListStr.AppendFormat("<a id='{0}' style='color:{1};margin:auto 3px;'>{2}</a>", this.UniqueID, PageIndexColor, i);
28.                        else
29.                            PageListStr.AppendFormat("<a id='{0}' style='color:{1};margin:auto 3px;' href=/"javascript:{2}/">{3}</a>", this.UniqueID, PageIndexColor, Page.ClientScript.GetCallbackEventReference(this, i.ToString(),"AjaxPagerCallBack",null), i);
30.                    }
31.                    PageListStr.AppendFormat(" {0}", PageInfo);
32.                    return PageListStr.ToString();
33.                }
34.                else
35.                {
36.                    for (int i = MinInt; i <= MaxInt; i++)
37.                    {
38.                        PageIndexColor = PageIndex == i ? "#CC0000" : "#000000";
39.                        if (PageIndex == i)
40.                            PageListStr.AppendFormat("<a id={0}' style='color:{1};margin:auto 3px;'>{2}</a>", this.UniqueID, PageIndexColor, i);
41.                        else
42.                            PageListStr.AppendFormat("<a id='{0}' style='color:{1};margin:auto 3px;' href=/"javascript:{2}/">{3}</a>", this.UniqueID, PageIndexColor, Page.ClientScript.GetCallbackEventReference(this, i.ToString(), "AjaxPagerCallBack", null), i);
43.                    }
44.                    if (PageIndex <= BarSize && TotalPage > BarSize)
45.                    {
46.                        PageListStr.AppendFormat("<a id='{0}' href=/"javascript:{1}/">下一页</a>", this.UniqueID, Page.ClientScript.GetCallbackEventReference(this, System.Convert.ToString(BarSize + 1), "AjaxPagerCallBack", null));
47.                    }
48.                    if (this.PageIndex > BarSize && (TotalPage - this.PageIndex) >= SingleNumber)
49.                    {
50.                        int MultiMinPageIndex = (IntPageForMax * BarSize);
51.                        int MultiMaxPageIndex = ((IntPageForMax + 1) * BarSize) + 1;
52.                        PageListStr.Insert(0, string.Format("<a id='{0}' href=/"javascript:{1}/">上一页</a>", this.UniqueID, Page.ClientScript.GetCallbackEventReference(this, MultiMinPageIndex.ToString(),"AjaxPagerCallBack",null)));
53.                        PageListStr.AppendFormat("<a id='{0}' href=/"javascript:{1}/">下一页</a>", this.UniqueID, Page.ClientScript.GetCallbackEventReference(this, MultiMaxPageIndex.ToString(),"AjaxPagerCallBack",null));
54.                    }
55.                    if (PageIndex > 10 && (TotalPage - PageIndex) < SingleNumber)
56.                    {
57.                        int MultiMinPageIndex = (IntPageForMax * BarSize);
58.                        PageListStr.Insert(0, string.Format("<a id='{0}' href=/"javascript:{1}/">上一页</a>", this.UniqueID, Page.ClientScript.GetCallbackEventReference(this, MultiMinPageIndex.ToString(), "AjaxPagerCallBack", null)));
59.                    }
60.                    PageListStr.AppendFormat(" {0}", PageInfo);
61.                    return PageListStr.ToString();
62.                }
63.            }
64.        }
65.        public void  BindData()
66.        {
67.            Repeater rpt = getRpt();
68.            rpt.Visible = true;
69.            SqlHelper helper;
70.            helper = this.Info.ConnectStringName.IsNullOrEmpty() ? new SqlHelper() : new SqlHelper(Info.ConnectStringName);
71.            if (this.Info.RepeaterUniqueID.IsNullOrEmpty())
72.            {
73.                throw new Exception("必须给Info的RepeaterUniqueID属性赋值");
74.            }
75.            int count = 0;
76.            DataTable dt = helper.GetPageData(Info.TableName, Info.Fields, Info.IdentityField, Info.PageSize, PageIndex, Info.IsDesc, Info.Content, out count);
77.            this.TotalRecord = count;
78.            rpt.DataShow(dt); 
79.        }
80.        private Repeater getRpt()
81.        { 
82.            return this.Page.FindControl(this.Info.RepeaterUniqueID) as Repeater;
83.        }
先感谢一下写那个Pager的人，GetContents(得到自己分页后的HTML)里我只做了少许改动，要不然还得细细算来！！
BindData(用到了我的SqlHelper)是利用为服务器的DataBind()方法把数据放到repeater里，只是不让它呈示，嘿嘿！
getRpt只是找到Repeater引用

维护视图状态
01.#region 维护视图状态
02.        protected override void LoadViewState(object savedState)
03.        {
04.            Triplet tp = savedState as Triplet;
05.            this.TotalRecord = Convert.ToInt32(tp.Third);
06.            this.Info = tp.Second as PageInfo;
07.            base.LoadViewState(tp.First);
08.        }
09.        protected override object SaveViewState()
10.        {
11.            Triplet tp = new Triplet();
12.            tp.First = base.SaveViewState();
13.            tp.Second = Info;
14.            tp.Third = this.TotalRecord;
15.            return tp;
16.        }
17.        #endregion
这里也不必说，只是PageInfo一定要能Serializable。

重写方法
01.#region 重写方法
02.        protected override void RenderContents(HtmlTextWriter writer)
03.        {
04.            writer.Write(GetContents());
05.            base.RenderContents(writer);
06.        }
07.        protected override void AddAttributesToRender(HtmlTextWriter writer)
08.        {
09.            writer.AddStyleAttribute("White-space", "nowrap");
10.            writer.AddStyleAttribute("padding-top", "2px");
11.            writer.AddStyleAttribute("padding-bottom", "2px");
12.            writer.AddStyleAttribute("color", "#949494");
13.            writer.AddStyleAttribute("font-weight", "bold");
14.            writer.AddStyleAttribute("background-color", this.BarBackGroundColor);
15.            base.AddAttributesToRender(writer);
16.        }
17.        #endregion
也不用说，大家一看都明白。

实现ICallbackEventHandler
01.#region ICallbackEventHandler 成员
02.        public string GetCallbackResult()
03.        {
04.            StringBuilder sb=new StringBuilder ();
05.            StringWriter sw=new StringWriter (sb);
06.            getRpt().RenderControl(new HtmlTextWriter(sw));
07.            return this.GetContents() + "[_]" + sb.ToString();
08.        }
09.        public void RaiseCallbackEvent(string eventArgument)
10.        {
11.            int pageindex = int.Parse(eventArgument);
12.            this._CurrentIndex = pageindex;
13.            BindData();
14.        }
15.        #endregion
回调时先执行RaiseCallbackEvent，所以CurrentIndex改变了， BindData()执行了！！！！
返回时时执行GetCallbackResult，string用"[_]"分开，对应上面注册的AjaxPagerCallBack js方法中的var parts =returnData.split('[_]');
OK！简单的Ajax分页就这样简单的完成了！！！

Northwind Orders表调用如下：
页面中Repeater包含在<div id="AjaxData"></div>中
代码
01.private void BindPage(string content)
02.        {
03.            SinoHelper.PageInfo info = new SinoHelper.PageInfo();
04.            info.PageSize = 5;
05.            info.RepeaterUniqueID = rpt.UniqueID;
06.            info.TableName = "Orders";
07.            info.Fields = "OrderID,CustomerID,ShipCity";
08.            info.IdentityField = "OrderID";
09.            info.Content = content;
10.            AjaxPager1.Info = info;
11.            AjaxPager1.BindData();
12.        }

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