返回完整結果linq分組查詢

Question

我想分組，並仍然檢索表中的所有數據。我對Linq還很陌生，似乎無法告訴我做錯了什麼。我不僅想對結果進行分組，而且還想檢索表格中的所有列。這可能嗎？

(from r in db.Form 
    orderby r.CreatedDate descending 
    group r by r.Record into myGroup 
    where myGroup.Count() > 0 
    where (r.CreatedDate > lastmonth) 
    where r.Name == "Test Name" 
    select new { r, myGroup.Key, Count = myGroup.Count() } 
    ) 

一些如何「r」失去其上下文或自從我分組「r」它已被替換。不確定。

Answer 1

您需要將任務分成兩個步驟來完成你想要的。

組數據

var groupedData = db.Form.Where(item=>item.CreatedDate > lastMonth && item.Name == "Test Name") 
        .OrderByDescending(item=>item.item.CreatedDate) 
        .GroupBy(item=>item.Record) 
        .Select(group => new {Groups = group, Key = group.Key, Count = group.Count()}) 
        .Where(item => item.Groups.Any()); 

從分組數據選擇Form元素

var formElements = groupedData.SelectMany(g => g.Groups).ToList(); 

Answer 2

既然你個人的記錄過濾，您應該分組，而不是前後進行篩選：

(
    from r in db.Form 
    where r.CreatedDate > lastMonth) 
    where r.Name == "Test Name" 
    orderby r.CreatedDate descending 
    group r by r.Record into myGroup 
    where myGroup.Count() > 0 
    select new { Groups = myGroup, myGroup.Key, Count = myGroup.Count() } 
) 
// Groups is a collection of db.Form instances