void dataBindByWhere()
??????? {

??????????? /**************select/distinct 練習(xí)*******************/
??????????? //獲取數(shù)據(jù)庫中的T_Student表數(shù)據(jù)
??????????? var list = from s in ctx.T_Student
?????????????????????? select s;
??????????? //采用匿名類型
??????????? var list1 = from s in ctx.T_Student
??????????????????????? select new
??????????????????????? {
??????????????????????????? stuNumber = s.stuNumber,
??????????????????????????? stuSex = s.stuSex,
??????????????????????????? //這里邊是可以計(jì)算的
??????????????????????????? stuAge = s.stuAge / 2 + s.stuAge / 2,
??????????????????????????? //也可以進(jìn)行條件判斷
??????????????????????????? stuAgeTime = s.stuAge>20?"成年":"年輕",
??????????????????????????? stuName = s.stuName
??????????????????????? };
??????????? //也可以不用匿名類型獲取個(gè)別字段值
??????????? var list2 = from s in ctx.T_Student
??????????????????????? select s.stuName;
??????????? //也可以轉(zhuǎn)化為自定義的類型,比如這里的peple為自定義的類型
??????????? var list3 = from s in ctx.T_Student
??????????????????????? select new People
??????????????????????????? {
??????????????????????????????? stuNumber = s.stuNumber,
??????????????????????????????? stuName = s.stuName
??????????????????????????? };
??????????? //可以在select 匿名類型里邊繼續(xù)包括匿名類型
??????????? var list4 = from s in ctx.T_Student
??????????????????????? select new
??????????????????????? {

??????????????????????????? stuNumber = s.stuNumber,
??????????????????????????? stuName = s.stuName,
??????????????????????????? stuInfo = new T_Student { stuAge = s.stuAge, stuSex = s.stuSex }
??????????????????????? };
??????????? //也可以繼續(xù)在select 里邊包括select
??????????? var list5 = from s in ctx.T_Student
??????????????????????? select new {
??????????????????????????? stuNumber = s.stuNumber,
??????????????????????????? stuSCore = from c in s.T_Score
?????????????????????????????????????? where s.stuNumber==c.stuNumber
?????????????????????????????????????? select c.score
??????????????????????? };
??????????? //也可以在select 里邊調(diào)用方法
??????????? var list6 = from s in ctx.T_Student
??????????????????????? select new {
??????????????????????????? stuNumber = s.stuNumber,
??????????????????????????? stuName = s.stuName,
??????????????????????????? stuAge = AgeInfo(s.stuAge)
??????????????????????? };
??????????? //也可以對(duì)查詢結(jié)果去除重復(fù)
??????????? var list7 = (from s in ctx.T_Student
???????????????????????? select s.stuName).Distinct();
??????????? GridView1.DataSource = list;
??????????? GridView1.DataBind();
??????? }
??????? string AgeInfo(int age)
??????? {
??????????? return age > 20 ? "成年" : "年輕";
??????? }

Linq無聊練習(xí)系列2--select/distinct練習(xí)