实体框架中的LIKE子句

Question

我必须搜索cityname like '%United States;AK;Adak%'所在的记录并在此基础上，将列的值存储在我的视图模型对象中。

我写了以下代码，当从一个数值进行强制转换时，它会导致一个错误，该数值必须小于无穷大。

zipcode=United States;AK;Adak;
var zipcd = (from u in db.ZipCodes1
             where u.CityName.Contains(zipcode) && u.CityType == "D"
             select u).ToList().Select(u => new Viewsearch
             {
                 Zipcode = u.ZIPCode,
                 CityName = u.CityName,
                 stateabbr = u.StateAbbr
             }).Distinct();
Viewsearch vs = (Viewsearch)zipcd;
if (zipcd.Count() > 1)
{
    locations = "United States;" + vs.stateabbr + ";" + vs.CityName;
}
else if (locations == "") 
{
    locations = "United States;" + vs.stateabbr + ";" + vs.CityName;
}
else
{
    locations = "United States;" + vs.stateabbr + ";" + vs.CityName + "," + locations;
}
if (zipcd.Count() > 3)
{
    locations = locations.Replace(locations, "," + "<br>");
}

Answer 1

编辑-这是与以前不同的错误消息吗？别介意

您的强制转换是错误的——您试图将查询的结果（可能有多个结果）强制转换为单个对象。

Viewsearch vs = (Viewsearch)zipcd;

您的zipcd是IQueryable<Viewsearch>，而不是Viewsearch。如果您只期望一个结果或希望分别使用第一个结果，或者您需要根据返回的对象的IEnumerable/IQueryable来编写代码，则可以使用Single()或First()。