LINQ表达式中的In子句 [英] In clause in linq expression

问题描述

我正在开发一个在线测试应用程序，该应用程序具有两个表类别和子类别，我希望借助类别和子类别从中选择一些问题.类似于(问题(1)中的类别ID和(1,2,3,4)中的subcategoryID

i am developing a online test application where have two tables category and subCategory from which i want to select some questions with the help of category and subcategory. something like ( question where category ID in (1) and subcategoryID in (1,2,3,4)

我正在获取要在查询中传递的子类别列表

I am getting list of subcategory that is going to pass in query

int[] subCategoryForQuestions=new int[]{1,2,3,4};

var TestDataList = coreDbContext.SolutionMasters
                       .Where(x => x.CategoryID == categoryID
                                   && x.DifficultyId == questionLevel
                                   && subCategoryForQuestions.Contains("here all value in Subcategory"))
                      .Take(NoOfQuestions);

或subcategoryID.contains("some value in array of integer")

我可以从任何人那里得到一些帮助吗?

can i get some help from anybody?

推荐答案

您可以按照 Linq到实体-SQL"IN"；条款.

int[] subCategoryForQuestions=new int[]{1,2,3,4};

var TestDataList = coreDbContext.SolutionMasters
                       .Where(x => x.CategoryID == categoryID
                                   && x.DifficultyId == questionLevel
                                   && subCategoryForQuestions.Contains(x.subcategoryID))
                      .Take(NoOfQuestions);

这将在幕后生成IN语句.您将要确保数组相对较小，以免在

This will generate an IN statement behind the scenes. You will want to ensure that the array is relatively small so you don't exhaust the SQL Server parameter limit.

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