Any: 用于检查序列中是否存在满足条件的元素。 代码语言:javascript 复制 bool hasItems=collection.Any(item=>item.Property>5); All: 用于检查序列中的所有元素是否都满足条件。 代码语言:javascript 复制 bool allMatch=collection.All(item=>item.Property>0); Count: 返回序列中满足条件的元素数量。 代码语言:ja...
步步为营VS 2008 + .NET 3.5(7) - LINQ查询操作符之First、FirstOrDefault、Last、LastOrDefault、ElementAt、ElementAtOrDefault、Contains、Any、All、Count、LongCount、Sum、Min、Max、Average、Aggregate、Cast、DefaultIfEmpty、SequenceEqual、OfType、ToArray、ToList、ToDictionary 作者:webabcd 介绍 ·First - 返...
Count、Max、Average和First就属于此类查询。 由于查询本身必须使用foreach来返回结果,因此这些方法在执行时不使用显式foreach语句。 这些查询返回单个值,而不是IEnumerable集合。 可以使用Enumerable.ToList或Enumerable.ToArray方法强制任何查询立即执行。 立即执行可重用查询结果,而不是查询声明。 结果被检索一次,然后存储...
Count() Average( 列) Sum( 列) Max( 列) Min( 列) Where( 条件) Any() All( 条件) 有关详细信息,请参阅 LinqDataSource Web Server Control Overview 和How to: Group and Aggregate Data Using the LinqDataSource Control. 适用于 产品版本 .NET Frame...
以下示例使用 Any 检查所有字符串是否以“o”开头。 class Market { public string Name { get; set; } public string[] Items { get; set; } } public static void Example() { List<Market> markets = new List<Market> { new Market { Name = "Emily's", Items = new string[] { "kiwi", ...
(cust.Orders.Count) msg &= "Average number of Orders per customer: " & _ averageOrderCount & vbCrLf Dim venezuelaTotalOrders = Aggregate cust In db.Customers _ Where cust.Country = "Venezuela" _ Into Sum(cust.Orders.Count) msg &= "Total number of orders from Customers in Venezuela: "...
() Console.WriteLine(count &" occurrence(s) of the search term """& _ searchTerm &""" were found.")' Keep console window open in debug mode.Console.WriteLine("Press any key to exit.") Console.ReadKey()EndSubEndClass' Output:' 3 occurrence(s) of the search term "data" were foun...
(cust.Orders.Count) msg &= "Average number of Orders per customer: " & averageOrderCount & vbCrLf Dim venezuelaTotalOrders = Aggregate cust In db.Customers Where cust.Country = "Venezuela" Into Sum(cust.Orders.Count) msg &= "Total number of orders from Customers in Venezuela: " & ...
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter. Exceptions 展开表 ExceptionCondition ArgumentNullException source is nulla null reference (N...
Therefore, you might catch any exceptions that are thrown by the XmlReader.Create overload methods and the XmlReader methods that read and parse the document. See also Parse Save WriteTo(XmlWriter) LINQ to XML overview Query an XDocument vs. query an XElement Applies to .NET 9 及其他版本...