ASP.NET 2.0 中動態添加 GridView 模板列

2024-07-10 13:12:35

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　　動態添加列，關鍵是實現 itemplate.instantiatein 方法。下面是一個添加 gridview 模板列的例子。

　　c#代碼

<%[email protected] page language="c#" %>
<%[email protected] import namespace="system.data" %>
<!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en"
"http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd">

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("-----請選擇------",""));
          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, "動態添加列");
      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)
    ...{
      //可以在這里訪問數據庫的其它字段的值，可以設置默認選擇項，具體應用，看自己的發揮了。
      //下面只是例子，舉一反三，不再費話了
      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動態添加模板列的例子</title>
</head>
<body>
<form id="form1" runat="server">
<asp:gridview id="gridview1" runat="server" autogeneratecolumns="false"
     onrowdatabound="gridview1_rowdatabound">
    <columns>
      <asp:boundfield headertext="標題" datafield="text"/>
    </columns>
</asp:gridview>
</form>
</body>
</html>