通過LINQ聲明返回記錄

Question

DataContext db = new DataContext(); 
Select_Utilities SelectedUtility = (from su in db.Select_Utilities 
            where su.id == SelectUtilityId 
            && su.Worksite_Id == WorksiteId 
            && su.Utility_Company.id == UtilityCompanyId 
            select su).FirstOrDefault(); 

然後我想說SelectedUtility.comment =「無論評論可能是什麼」。

，但得到錯誤：無法含蓄轉換型「Select_Utility」到「Select_Utilities」

在聲明中「FirstOrDefault」 ....任何建議？

感謝

Answer 1

更改結果類型Select_Utility

Select_Utility SelectedUtility = // here 
    (from su in db.Select_Utilities 
    where su.id == SelectUtilityId && 
      su.Worksite_Id == WorksiteId && 
      su.Utility_Company.id == UtilityCompanyId 
    select su).FirstOrDefault(); 

Answer 2

我猜Select_Utilities是你的實體表的其中ruturns Select_Utility對象的集合名稱。嘗試：

Select_Utility selectedUtility = (from su in db.Select_Utilities 
            where su.id == SelectUtilityId 
            && su.Worksite_Id == WorksiteId 
            && su.Utility_Company.id == UtilityCompanyId 
            select su).FirstOrDefault();