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。
<![CDATA[
<%@ 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>
]]>
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