后台定义一个绑定函数;pagelode里边调用bind();
public void Bind()
{
DataTable dtInfo = 要绑定的数据;
DataRow dr = dtInfo.NewRow();
dr["TypeName"] = "全部";//添加全部选项
dr["nID"] = "-1";
dtInfo.Rows.InsertAt(dr,0);
this.下拉列表id.DataSource = dtInfo;
this.dd下拉列表idataTextField = "显示字段";
this.下拉列表id.DataValueField = "值字段";
this.下拉列表id.DataBind();
}