Select用法varselectedItems =fromiteminitemswhereitem.ParentID == parentIDorderbyitem.SortIndex descending ,item.Name ascendingselectitem;0.1where:varlist=collection.Where(t => (txtCustomerName.Text.Trim().Length ==0|| t.ClientName.ToUpper().IndexOf(txtCustomerName.Text.Trim().ToUpper()) >=0...
15、GroupJoin操作符也用于连接两个输入序列,但与Join操作符不同稍有不同,Join操作符在列举outer序列元素时,会将一个outer序列元素和其对应的inner序列元素作为一组参数传递给委托resultSelector委托,这就意味着如果某一个outer序列元素有多个对应的inner序列元素,Join操作符将会分多次将outer序列元素和每一个对应的inne...
展方法 Where()和 Select(),会生成与前面 LINQ 查询一样的结果: /// <summary> /// 过滤,带扩展方法的复杂查询 /// </summary> private static void SimpleFiltering() { //var racers = from r in Formula1.GetChampions() // where r.Wins > 15 && (r.Country == "Brazil" || r.Country =...
LinQ标准的查询操作符 过滤where,index1,oftype 本文章为转载内容,我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题,欢迎原作者联系我们进行内容更正或删除文章。
arrayFilter() -> Where() arrayFirst() -> First() arrayForEach() -> (no direct equivalent) arrayGetDistictValues() -> Distinct() arrayIndexOf() -> IndexOf() arrayMap() -> Select() arrayPushAll() -> (no direct equivalent) arrayRemoveItem() -> (no direct equivalent) compareArrays(...
LINQ to SQL usesSqlMetal.exethat comes as part of theWindows SDKor the “LINQ to SQL Classes” item in Visual Studio to automatically generate the entity classes. As our provider uses a very similar mapping technique to LINQ to SQL, we can still use these tools to auto-generate the entit...
在LINQ(Language Integrated Query)表达式中,In子句用于指定一个集合,然后在查询中判断某个值是否存在于该集合中。它类似于SQL语句中的IN关键字。 In子句的语法如下: 代码语言:csharp 复制 var result = from item in collection where item.PropertyName In collection select item; 其中,collection是一个集合,Prope...
The Enumerable.Where method allows you to specify a condition that filters the input sequence. A second overloaded version provides access to the index of each item in the collection so you can filter based on the index as well. The following example uses both the Where and Select methods, ...
'System.Array' does not contain a definition for 'Select' and no extension method 'Select' 'System.Windows.Forms.Button' does not contain a definition 'System.Xml.XmlException' occurred in System.Xml.dll Visual C#? 'Transaction failed. The server response was: 5.7.1 Relay access denied in ...
// In this case we can ignore "item" itself. int count = sequence.Aggregate(0, (current, item) => current + 1); Or perhaps summing all the lengths of strings in a sequence of strings: int total = sequence.Aggregate(0, (current, item) => current + item.Length); Personally I ...