在.NET中使用简单的值绑定表达式

        用过JSF的，相信值绑定表达式不会太陌生。值绑定表达式就是像#{somebean.somevariable}这样简单的东东，JSF处理这样的表达式然后创建数据以便在JSF生命周期的后续阶段使用。
       使用表达式，对于.NET来说，简化了一些数据表的制作，对于复杂的表格尤其有显著效果。

一、代码介绍：

/**/ /*----------------------------------------------------------------
// 文件名：        table.cs
//
//    目前已经支持域绑定#{字段名}如公司名：#{productname}，序列绑定#{@seq} 如sy_#{@seq}则为sy_0,sy_1,sy_2……，
//    param绑定#{@param:}如#{@param:autoid}则为地址栏传过来的autoid，自定义值#{@custom:} 如#{@custom:myval}，
//    多表值域#{表名.字段名} 如#{userinfo.userid}，排序列绑定@{字段名}如class="@{companyname} 表示公司名列要应用样式绑定式排序"，
//    枚举绑定 如新旧程度：#{oldlevel!0:全新,1:九成新,2:八成新,3:七成新,4:五成新} 如oldlevel字段为3则显示7成新 等格式
//
//
// 
// 不会飞的鱼
//----------------------------------------------------------------*/
using  System;
using  System.Web;
using  System.Web.UI;
using  System.Collections;
using  System.Data;
using  vista.Util.Data;

namespace  ViewLogic.UI 
... {

    public class table : Control 
    ...{
        private IDataSource _dataSource = null;
        private IList _columnList = null;
        private string _sortDirect = null;
        private string _colname = null;
        private System.Collections.Specialized.NameValueCollection _params = null;
        private IDictionary _customvalue = null;

        public IDataSource DataSource 
        ...{
            get 
            ...{
                return _dataSource;
            }
            set 
            ...{
                _dataSource = value;
            }
        }

        public System.Collections.Specialized.NameValueCollection Params 
        ...{
            get...{return _params;}
            set...{_params = value;}
        }

        public IDictionary CustomValue
        ...{
            get...{return _customvalue;}
            set...{_customvalue = value;}
        }

        public IList ColumnList 
        ...{
            get 
            ...{
                if(DataSource==null)
                    return null;
                string htmlSource = ((LiteralControl) Controls[0]).Text;
                System.Text.RegularExpressions.MatchCollection mc = System.Text.RegularExpressions.Regex.Matches(htmlSource,@"#{[@w]+}");
                
                _columnList = new ArrayList(mc.Count);

                foreach(System.Text.RegularExpressions.Match m in mc) 
                ...{
                    string colName = System.Text.RegularExpressions.Regex.Replace(m.Groups[0].Value,@"[#{}]","");
                    if(colName.IndexOf("@")!=0) 
                    ...{
                        _columnList.Add(colName);
                    }                    
                }
                return _columnList;
            }
        }

        public string ColName 
        ...{
            set ...{ _colname = value;}
        }


        public string SortDriect 
        ...{
            set 
            ...{
                _sortDirect = value;
            }
        }

        protected override void Render(HtmlTextWriter output) 
        ...{

            if ( (HasControls()) && (Controls[0] is LiteralControl) && _dataSource!=null) 
            ...{
                string htmlSource = ((LiteralControl) Controls[0]).Text;
                bool flag = true;
                int i=0;
                if(_sortDirect!=null) 
                ...{
                    htmlSource = htmlSource.Replace("@{"+ _colname +"}","sortOrder"+_sortDirect);
                }

                while(_dataSource.MoveNext()) 
                ...{
                    DataRow dr = _dataSource.Current as DataRow;
                    i ++;
                    System.Text.RegularExpressions.MatchCollection mc = System.Text.RegularExpressions.Regex.Matches(htmlSource,@"#{[@!.,:w]+}");
                    string outstr = htmlSource;

                    foreach(System.Text.RegularExpressions.Match m in mc) 
                    ...{

                        string colName = System.Text.RegularExpressions.Regex.Replace(m.Groups[0].Value,@"[#{}]","");
                        if(colName.IndexOf("@")==0) 
                        ...{
                            if(colName.Trim().Equals("@seq"))
                                outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,i.ToString());
                            else if(colName.Trim().IndexOf("@param:") == 0) 
                            ...{
                                string[] pars = colName.Split(':');
                                string realparam = pars[1];

                                outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,Params[realparam].ToString());
                            }
                            else if(colName.Trim().IndexOf("@custom:") == 0) 
                            ...{
                                string[] customs = colName.Split(':');
                                string realcustom = customs[1];
                                if(CustomValue[realcustom] is string)
                                    outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,CustomValue[realcustom].ToString());
                                else if(CustomValue[realcustom] is IList) 
                                ...{
                                    string temp = (CustomValue[realcustom] as IList)[i-1].ToString();
                                    outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,temp);
                                }

                            }
                        }
                        else if(colName.IndexOf(".")!=-1) 
                        ...{                           
                            string[] colNameSplit = colName.Split('.');
                            DataTable dt = dr.Table.DataSet.Tables[colNameSplit[0]];
                            foreach(DataRow dr2 in dt.Rows)
                            ...{
                                outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,dr2[colNameSplit[1]].ToString());
                            }
                        }
                        else 
                        ...{
                            if(colName.IndexOf("!")!=-1) 
                            ...{
                                string[] exps = colName.Split('!');
                                string explist = exps[1];
                                string[] expitems = explist.Split(',');
                                bool fFound = false;
                                foreach(string expitem in expitems) 
                                ...{
                                    string[] hashitem = expitem.Split(':');

                                    if(hashitem[0]==dr[exps[0]].ToString()) 
                                    ...{
                                        string realoutput = hashitem[1];
                                        outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,realoutput);
                                        flag = true;
                                        break;
                                    }
                                }
                                if(!fFound) 
                                ...{
                                    outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,"");
                                }
                            }
                            else 
                            ...{
                                outstr = System.Text.RegularExpressions.Regex.Replace(outstr,m.Groups[0].Value,dr[colName].ToString());
                            }
                        }

                    }
                    output.Write(outstr);
                    flag = false;
                }
                
            }
        }

        

    }    
}

 IDataSource接口，为table.cs提供数据源：

 

using  System;
using  System.Collections;

namespace  ViewLogic.Data
... {
    /**//// <summary>
    /// IDataSource是一个通用的数据接口，有一个方法GetDataField
    /// </summary>
    public interface IDataSource : IEnumerator
    ...{
        /**//// <summary>
        /// GetDataField方法，取得指定名称域的值
        /// </summary>
        /// <param name="name">域的名称</param>
        /// <returns></returns>
        string GetDataField(string name);
    }
}

 工厂类，具体数据来源的创建，想要什么就制作什么，比如下面的DataSet,DataTable或者更多：

using  System;
using  System.Data;

namespace  ViewLogic.Data
... {
    /**//// <summary>
    /// DataSourceFactory为工厂类，返回IDataSource接口类型
    /// </summary>
    public class DataSourceFactory
    ...{
        public DataSourceFactory()
        ...{
        }

        /**//// <summary>
        /// 
        /// </summary>
        /// <param name="ds">DataSet</param>
        /// <returns></returns>
        public static IDataSource Create(DataSet ds)
        ...{
            return Create(ds.Tables[0]);
        }

        /**//// <summary>
        /// 
        /// </summary>
        /// <param name="dt">DataTable</param>
        /// <returns></returns>
        public static IDataSource Create(DataTable dt)
        ...{
            return new DataList(dt);
        }
    }
}

基类：

using  System;
using  System.Collections;
using  System.Reflection;

namespace  ViewLogic.Data
... {
    /**//// <summary>
    /// DataBase 的摘要说明。
    /// </summary>
    public abstract class DataBase : IDataSource
    ...{
        public DataBase()
        ...{
        }

        /**//// <summary>
        /// 
        /// </summary>
        private IEnumerator enumerator;

        /**//// <summary>
        /// 
        /// </summary>
        protected IEnumerator Enumerator
        ...{
            get 
            ...{ 
                return enumerator; 
            }
            set 
            ...{ 
                enumerator = value; 
            }
        }

        IDataSource 成员#region IDataSource 成员

        /**//// <summary>
        /// GetDataField
        /// </summary>
        /// <param name="name">string</param>
        /// <returns></returns>
        public abstract string GetDataField(string name);

        #endregion

        IEnumerator 成员#region IEnumerator 成员

        /**//// <summary>
        /// 
        /// </summary>
        public void Reset()
        ...{
            enumerator.Reset();
        }

        /**//// <summary>
        /// 
        /// </summary>
        public object Current
        ...{
            get
            ...{
                return enumerator.Current;
            }
        }

        /**//// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public bool MoveNext()
        ...{
            return enumerator.MoveNext();
        }

        #endregion
    }
}

具体的操作：

using  System;
using  System.Data;

namespace  ViewLogic.Data
... {
    /**//// <summary>
    /// DataList 的摘要说明。
    /// </summary>
    public class DataList : DataBase
    ...{
        protected DataList()
        ...{
        }

        /**//// <summary>
        /// DataList
        /// </summary>
        /// <param name="table">DataTable</param>
        public DataList(DataTable table)
        ...{
            this.Enumerator = table.Rows.GetEnumerator();
        }

        /**//// <summary>
        /// GetDataField
        /// </summary>
        /// <param name="name">string</param>
        /// <returns>string</returns>
        public override string GetDataField(string name)
        ...{
            if(Enumerator.Current != null)
            ...{
                DataRow row = Enumerator.Current as DataRow;
                if(row != null)
                ...{
                    return row[name].ToString();
                }
                else
                ...{
                    return null;
                }
            }
            else
            ...{
                return null;
            }
        }
    }

}

二、使用：

      1、准备工作：因为是自定义控件，所以要引用进来<%@  Register TagPrefix="tbl" Namespace="ViewLogic.UI" Assembly="ViewLogic"%>

     2、简单前台绑定：

< table >
         < tr >
                 < td > 姓名 </ td >
                 < td > 年龄 </ td >
         </ tr >

           <tbl:table id="tbl1" runat="server">
         < tr >
                 < td > #{username} </ td >
                 < td > #{age} </ td >
         </ tr >

            </tbl:table>
</ table >

     对应后台绑定：

           声明：protected ViewLogic.UI.table tbl1;
           绑定：tbl1.DataSource = DataSourceFactory.Create(dt);   // dt 为 一个DataTable的实例
                       tbl1.DataBind();

            OK，可以使用了。当然，你的dt 里面要包含username和age这两个列

     3、序列绑定：

                             排名      姓名
                              1        wang
                              2        zhang
                              3            li

            而 1、2、3是图片img_1.gif,img_2.gif,img_3.gif

则

< table >
         < tr >
                 < td >排 名 </ td >
                 < td > 姓名 </ td >
         </ tr >

           <tbl:table id="tbl1" runat="server">
         < tr >
                 < td ><img src="img"</td _#{@seq}.gif >
                 < td > #{age} </ td >
         </ tr >

            </tbl:table>
</ table >

         后台绑定同2的后台

        4、多表绑定：同2，只是#{表名.列名}的形式，并且，绑定的DataSet里的Table[0]可以省去表明直接写
                                  #{列名}，而DataSet里的Tables[1]绑定列则必须写Table[1]的名字，比如#{tb1.age}

        5、传值绑定：
                                包括地址栏和自定义两种：

                              1）  地址栏传值： 

                              前台：  如a.aspx?id=1 页面里有 <a href="test.aspx?id=#{@param:id}">查看详细</a>
                               则 <a href="test.aspx?id=1">查看详细</a>

                               后台： tbl1.Params = Request.Params;

                             2）  自定义传值：

                             前台：假设<a href="test.aspx?id=#{@custom:bookid}&year=#{@custom:year}">查看书目</a>

                             后台： Hashtable ht = new Hashtable();

                                           ht.add("bookid","1");

                                           ht.add("year","2006");

                                           也可以进行一键多值绑定：

                                          Hashtable ht = new Hashtable();

                                           ht.add("bookid","1");

                                           ArrayList ar = new ArrayList();

                                          ar.Add("2006");

                                          ar.Add("2007");

                                          ………………

                                           ht.add("year",ar);

          6、枚举绑定：

                           前台：<TD>新旧程度：#{oldlevel!0:全新,1:九成新,2:八成新,3:七成新,4:五成新}</TD>

                          后台：同2绑定。

                          如果列oldlevel 值为 3 则显示 七成新

          7、排序绑定：

                         结合我的《样式绑定驱动脚本……》一文，进行前台的排序样式绑定。

好了完成了，还是那句话，DEMO，DEMO而已，为的是发散思维，拓宽思路，当然大家完全可以自己制作这些代码，关键是思想，用.NET进行快速开发确实还有很长的路要走，asp.net的硬框架也不如J2EE的众多框架那样灵活，所以还要有天才的大家们共同研究………………