LINQ Query下拉列表数据源不起作用

Question

我有一个system.Linq.Enumerable.WhereListIterator，它返回的值如下图所示 [

但是当我将此添加到列表然后添加到下拉数据源时，它不起作用

请帮忙

这是我的代码

using (var dr = db.ExecuteDataReader("GetDealersWithDiscount", CommandType.StoredProcedure, param))
        {
            while (dr.Read())
            {
                dealers.Add(new Dealer
                {
                    Name = Convert.ToString(dr["dealer_name"]),
                    Adress = Convert.ToString(dr["dealer_address"]),
                    Zipcode = Convert.ToString(dr["dealer_zip_code"]),
                    Image = Convert.ToString(dr["dealer_name"]),
                    Manufacturer = Convert.ToString(dr["manufacturer_id"])
                });
            }

        }

事件

string[] zipcodes = strzipcode.Split(',');
List<Dealer> filterList = new List<Dealer>();
filterList.Add(new Dealer
{
    Zipcode = txtZipCode.Text.Trim()
});
for (int x = 0; x < zipcodes.Length-1; x++)
{
    filterList.Add(new Dealer
    {
        Zipcode = zipcodes[x]
    });
}
var filteredFileSet = dealers.Where(i => filterList.Contains(i));
dtlSanPham.DataSource = filteredFileSet.ToList();
dtlSanPham.DataBind();

Answer 1

您似乎只在filterList创建新的经销商，只有一个邮政编码，然后将它们与dealers列表中包含Zipcodes的经销商以及其他信息进行比较（这意味着他们将从不匹配。）

不要将经销商与经销商进行比较，而是尝试创建一个List<string>只是拉链码，并对其进行过滤。在where子句中，您需要引用ZipCode类的字符串属性或覆盖类中的ToString()以显示它。 How to override ToString()

Where(i => filterList.Contains(i.ZipCode.Value));

或

Where(i => filterList.Contains(i.ZipCode.ToString()));

string[] zipcodes = strzipcode.Split(',');
List<string> filterList = new List<string>();
filterList.Add(txtZipCode.Text.Trim());

zipcodes.ForEach(zipCode => {
  filterList.Add(zipCode);
})

var filteredFileSet = dealers.Where(i => filterList.Contains(i.ZipCode.Value));
dtlSanPham.DataSource = filteredFileSet.ToList();
dtlSanPham.DataBind();