如何在字符串列表中选择/过滤子字符串?

如果我理解正确,您希望获得按ID排序的前20个活动,其Referrer字段不包含MyDomains中的任何项目作为子字符串。

以下方法或类似方法应该有效:

var theActivities = (from a in dc.Activities
    where a.Referrer != null
        && a.Referrer.Trim().Length > 0
        && a.SearchResults.Count() == 0
    select a);

foreach(var domain in MyDomains) {
    theActivities = theActivities.Except(dc.Activities.Where(a => a.Referrer.Contains(domain)));
}

theActivities = theActivities.OrderBy(a => a.Id).Take(20);

//Now you can query theActivities

:事实上,这不起作用。由于查询表达式在实际查询时被计算,因此所有 Except domain

var whereClauses=new List<string>();

for(int i=0; i<MyDomains.Length; i++) {
    whereClauses.Add(string.Format("(Referrer like {{{0}}})", i));
}

var sqlFormattedDomains=MyDomains.Select(d => string.Format("%{0}%", d)).ToArray();

var sqlCommand=string.Format(
    "select top 20 * from Activities where (not Referrer is null) and (not ({0})) order by Id",
    sqlFormattedDomains.Join(" or "));

var x=dc.ExecuteQuery<Activities>(sqlCommand, sqlFormattedDomains);

SearchResults.Count() == 0

&& !MyDomains.Contains(a.Referrer)