The examples in this topic demonstrate how to use the Join method to query a DataSet using the method query syntax. The FillDataSet method used in these examples is specified in Loading Data Into a DataSet. The
int[] numbers = [5,10,8,3,6,12];//Query syntax:IEnumerable<int> numQuery1 =fromnuminnumberswherenum %2==0orderbynumselectnum;//Method syntax:IEnumerable<int> numQuery2 = numbers .Where(num => num %2==0) .OrderBy(n => n);foreach(intiinnumQuery1) { Console.Write(i +" ")...
1classQueryVMethodSyntax2{3staticvoidMain()4{5int[] numbers = {5,10,8,3,6,12};67// 查询语法8IEnumerable<int> numQuery1 =9fromnuminnumbers10wherenum %2==011orderbynum12selectnum;1314// 方法语法15IEnumerable<int> numQuery2 = numbers.Where(num => num %2==0).OrderBy(n =>n);16...
int[] numbers = [ 5, 10, 8, 3, 6, 12 ]; //Query syntax: IEnumerable<int> numQuery1 = from num in numbers where num % 2 == 0 orderby num select num; //Method syntax: IEnumerable<int> numQuery2 = numbers .Where(num => num % 2 == 0) .OrderBy(n => n); foreach (in...
query expressions are translated to something that the CLR does understand: method calls. These methods are called thestandard query operators, and they have names such asWhere,Select,GroupBy,Join,Max,Average, and so on. You can call them directly by using method syntax instead of query syntax...
上面的第一种方法叫查询语法(query syntax),看上去和SQL的语句很相似。查询语法使用查询表达式书写。第二种方法叫方法语法(method syntax)是命令形式,它使用的是标准的方法调用,方法是一组叫做标准查询运算符的方法。虽然形式上这两种查询方法不同,事实上这两种方法存在着紧密的联系,在CLR内只识别查询方法,因此在每次...
// Using method-based query syntax. var query2 = words. GroupBy(w => w.Length, w => w.ToUpper()). Select(g => new { Length = g.Key, Words = g }). OrderBy(o => o.Length); foreach (var obj in query) { Console.WriteLine("Words of length {0}:", obj.Length); ...
Query syntax fromouter-varinouter-enumerablejoininner-varininner-enumerableonouter-key-exprequalsinner-key-expr[ into identifier ] Overview Join 和 GroupJoin 将两个输入序列网格化为一个输出序列。 Join 发出平坦的输出; GroupJoin 发出分层输出。
This differs from the use of SelectMany, which requires more than one method call to perform the same operation. Join preserves the order of the elements of outer, and for each of these elements, the order of the matching elements of inner. In query expression syntax, a join (C#) or ...
上面我们展示了 LINQ的两种语法Query Syntax Method syntax 一个是类似sql的query语法(这是比较流行的写法,通俗易懂) 一个是method语法(用到了Lambda表达式,就是name => name.Length <= 8这儿) Lambda 表达式 用=>分开,左边是参数,可以有多个参数,在上面的例子里是name这个参数,name只是个形参,随便写啥都行,写...