小编use*_*089的帖子

我有Executequery的问题:错误消息:"指定的强制转换无效".我试过了:

var qq = db.ExecuteQuery<class_search>(query, ddl4, ddl5, ddl1).ToList();

但同样的错误也是如此.我试过几个方法.总是这个错误或"查询结果不能多​​次枚举",当我尝试做IEnumerable时.我读了很多文章,但我不知道怎么做.我做错了什么,或者错过了什么？

public class class_search
{
    public string path_image
    { get; set; }

    public string name_product
    { get; set; }

    public float cost
    { get; set; }
} 

public partial class Search : System.Web.UI.Page
{
    DataClasses1DataContext db = new DataClasses1DataContext();

    string ddl4 = DropDownList4.SelectedItem.Value;
    string ddl5 = DropDownList5.SelectedItem.Value;
    string ddl1 = DropDownList1.SelectedItem.Value;

    string query = "select p.path_image, p.name_product, p.cost from Table1 a, Table2  p, Table3 k where a.column1 = {0} and a.column2 = …