ASP.NET 2.0 中动态添加 GridView 模板列的例子

动态添加列，关键是实现 ITemplate.InstantiateIn 方法。下面是一个添加 GridView 模板列的例子。

<% @ Page Language = " C# "   %>
<% @ Import Namespace = " System.Data "   %>
<! DOCTYPE html PUBLIC  " -//W3C//DTD XHTML 1.0 Transitional//EN "
  " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >

< script runat = " server " >
  ICollection CreateDataSource()
  {
    DataTable dt  =   new  DataTable();
    DataRow dr;
    dt.Columns.Add( new  DataColumn( " id " ,  typeof (Int32)));
    dt.Columns.Add( new  DataColumn( " text " ,  typeof ( string )));
     for  ( int  i  =   0 ; i  <   6 ; i ++ )
    {
      dr  =  dt.NewRow();
      dr[ 0 ]  =  i;
      dr[ 1 ]  =   " 列表项目  "   +  i.ToString();
      dt.Rows.Add(dr);
    }
    DataView dv  =   new  DataView(dt);
     return  dv;
  }

   public   class  GridViewTemplate : ITemplate
  {
     private  DataControlRowType templateType;
     private   string  columnName;

     public  GridViewTemplate( DataControlRowType type,  string  colname )
    {
      templateType  =  type;
      columnName  =  colname;
    }

     public   void  InstantiateIn( System.Web.UI.Control container )
    {
       switch  (templateType)
      {
         case  DataControlRowType.Header:
          Literal lc  =   new  Literal();
          lc.Text  =  columnName;          
          container.Controls.Add(lc);          
           break ;
         case  DataControlRowType.DataRow:
          DropDownList drr  =   new  DropDownList();
          drr.ID  =   " dropdown " ;
          drr.AppendDataBoundItems  =   true ;
          drr.Items.Add( new  ListItem( " -----请选择------ " , "" ));
          drr.Items.Add( new  ListItem( " AA " ,  " a " ));
          drr.Items.Add( new  ListItem( " BB " ,  " b " ));
          drr.Items.Add( new  ListItem( " CC " ,  " c " ));
          container.Controls.Add(drr);
           break ;
         default :
          break ;
      }
    }
  }
  
   protected   void  Page_Load( object  sender, EventArgs e)
  {
     if  ( ! IsPostBack)
    {
      TemplateField customField  =   new  TemplateField();
      customField.ShowHeader  =   true ;
      customField.HeaderTemplate  =   new  GridViewTemplate(DataControlRowType.Header,  " 动态添加列 " );
      customField.ItemTemplate  =   new  GridViewTemplate(DataControlRowType.DataRow,  "" );
      GridView1.Columns.Add(customField);
      GridView1.DataSource  =  CreateDataSource();
      GridView1.DataBind();
    }
  }

   protected   void  GridView1_RowDataBound(  object  sender, GridViewRowEventArgs e )
  {
     if  (e.Row.RowType  ==  DataControlRowType.DataRow)
    {
       // 可以在这里访问数据库的其它字段的值，可以设置默认选择项，具体应用，看自己的发挥了。
       // 下面只是例子，举一反三，不再费话了
      DataRowView gv  =  (DataRowView)e.Row.DataItem;
       int  itemSeleted  =  Int32.Parse(gv.Row[ " id " ].ToString())  >   3   ?   0  : Int32.Parse(gv.Row[ " id " ].ToString());
      DropDownList dr  =  (DropDownList)e.Row.FindControl( " dropdown " );
      dr.SelectedIndex  =  itemSeleted;
    }
  }
</ script >

< html xmlns = " http://www.w3.org/1999/xhtml " >
< head id = " Head1 "  runat = " server " >
   < title > GridView动态添加模板列的例子 </ title >
</ head >
< body >
< form id = " form1 "  runat = " server " >
   < asp:GridView ID = " GridView1 "  runat = " server "  AutoGenerateColumns = " False "
     OnRowDataBound = " GridView1_RowDataBound " >
     < Columns >
       < asp:BoundField HeaderText = " 标题 "   DataField = " text " />
     </ Columns >
   </ asp:GridView >  
</ form >
</ body >
</ html >