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根据我的要求，我设法从这个站点获得了一个 linq 查询，但是当我将整个内容粘贴到 linq pad 时它会出错。在这里，我将粘贴完整的 linq 查询，其中出现错误消息，例如“名称 'grp' 在当前上下文中不存在”

void Main()
{
    List<SearchResult> list = new List<SearchResult>() {
    new SearchResult(){ID=4,Title="Wie man BBA reman erreicht"},
    new SearchResult(){ID=5,Title="Ersatz Airbags, Gurtstrammer und Auto Körper Teile "},
    new SearchResult(){ID=6,Title="JCB Excavator - ECU P/N: 728/35700"},
    new SearchResult(){ID=2,Title="Geo Prism 1995 GEO - ABS #16213899"},
    new SearchResult(){ID=3,Title="Geo Prism 1995 - ABS #16213899"},
    new SearchResult(){ID=1,Title="Geo Prism 1995 GEO GEO- ABS #16213899"},
    };

var to_search = new[] { "Geo", "JCB" };
var result = (from searchResult in list
             let title = searchResult.Title.ToLower()
             let key_string = to_search.FirstOrDefault(ts => title.Contains(ts))
             orderby key_string == null ? -1 : title.Split(new[] { key_string }, StringSplitOptions.None).Length descending
             group searchResult by key_string into Group
             select Group).OrderByDescending(grp => grp.Count()).ThenByDescending(CountStringOccurrences(**grp.Key**, to_search));
}

public int CountStringOccurrences(string text, string[] pattern)
{
// Loop through all instances of the string 'text'.
int count = 0;
foreach (string itm in pattern)
{ 
   int i = 0;
   while ((i = text.IndexOf(itm, i)) != -1)
   {
      i += itm.Length;
      count++;
    }
}
return count;
 }

public class SearchResult{
    public int ID { get; set; }
    public string Title { get; set; }
}

粗体区域抛出错误。谢谢请看。

4

1 回答 1

2

将查询的结尾从

ThenByDescending(CountStringOccurrences(grp.Key, to_search));

至

ThenByDescending(grp => CountStringOccurrences(grp.Key, to_search));

因为Enumerable.ThenByDescending需要 keySelector 函数并且您想要传递searchresult-Group。

于 2012-07-11T10:06:10.967 回答