首先 什么是linq呢 ？

LINQ即Language Integrated Query(語言集成查詢)，LINQ是集成到C#和Visual Basic.NET這些語言中用于提供查詢數(shù)據(jù)能力的一個(gè)新特性。

它是.NET框架的擴(kuò)展，它允許我們以數(shù)據(jù)庫查詢的方式查詢數(shù)據(jù)集合。

借助于LINQ技術(shù)，我們可以使用一種類似SQL的語法來查詢?nèi)魏涡问降臄?shù)據(jù)。

接下來講講我工作中用到的

linq中的數(shù)組篩選數(shù)據(jù)庫中的數(shù)據(jù)

 public List GetList1(string cardPhone,string[] carNo)
        {
            var q = from r in DB().TAB_TEL_ADVISORY
                    where r.CUST_TEL == cardPhone || carNo.Contains(r.CAR_NO)
                    select new TelAdvisory
                    {
                        ID = r.ID,
                        CustTel = r.CUST_TEL,
                        CustName = r.CUST_NAME,
                        CarNo = r.CAR_NO,
                        AdvisoryContent = r.ADVISORY_CONTENT,
                        AdvisoryDate = r.ADVISORY_DATE,
                        AnswerResult = r.ANSWER_RESULT,
                        Server = r.SERVER,
                    };
            return q.ToList();
        }

LINQ中的增刪改都要調(diào)用SubmitChanges方法

public bool ResetPassWord(UserType type, int userId, string newCryptPassword)
        {
            var db = DB();
            try
            {
                switch (type)
                {
                    case UserType.雇員:
                        {
                            var tab = db.TAB_EMPLOYEE.Single(r => r.ID == userId);
                            tab.LOGIN_PWD = newCryptPassword;
                            break;
                        }
                    case UserType.合作商:
                        {
                            var tab = db.TAB_PARTNER.Single(r => r.ID == userId);
                            tab.LOGIN_PWD = newCryptPassword;
                            break;
                        }
                }
                db.SubmitChanges();
                return true;
            }
            catch
            {
                return false;
            }
        }

db.account.DeleteOnSubmit(account);
db.account.InsertOnSubmit(account);
 db.SubmitChanges();

linq中的搜索條件，傳入的參數(shù)是空的或者有值的，或者是關(guān)鍵字

query = (from r in db.TAB_PARTNER
               where ((partnerType != -1 && r.partner_type == partnerType) || partnerType == -1) 

               && ((searchKey != "" && r.PARTNER_NAME.IndexOf(searchKey) > -1) || searchKey == "") 

                orderby r.partner_type ascending

linq to sql分頁的問題

       Skip(100)代表跳過100行后.從第101行開始分頁;

       take(10)表示多少行分頁; pagesize為每頁顯示的數(shù)據(jù)條數(shù)

       q.Skip(PageSize * (CurrentPage - 1)).Take(PageSize).ToList();