linq extension methods

How does php obtain the file extension? Php file extension methods How to obtain the file extension in php, how to obtain the file extension in php, and how to obtain the file extension in php through examples. The exampl

the Memcache extension in PHP, a problem is found, and the SESSION will be lost. This may be because no port 11211 is added to the firewall when the Memcached server is installed, After the firewall rules are modified, everything is normal. PHP memcached extension installation (note here is memcached non memcache) wget https://launchpad.net/libmemcached/1.0/1.0.16/+download/libmemcached-1.0.16.tar.gz tar-z

Tree is repeatedly generated every time, generating an SQL statement is costly and inefficient. Therefore, you can use the compile query function to compile the unchanged part and add the part to be changed. Example: // Compile the query core var query1 = compiledquery. compile (northwnddatacontext DC1, string initialchar) => from C in dc1.mers MERs where c. customerid. startswith (initialchar) Select C); foreach (VAR Item1 in new [] {"A", "B", "C", "D "}) {// call method var query = query1 (DC

Method 1. Official example As we all know, it is also a method that many opponents of the LINQ to SQL think is inefficient. NorthwinddatacontextDB =NewNorthwinddatacontext();VaRCustomers = dB. Customers. Where (C => C. customerid. startswith ("Bl"));Foreach(VaRCustomerInCustomers) {customer. Address ="Guangzhou"; Customer. contactname ="Coolcode"; Customer. companyName ="Microsoft";} DB. submitchanges (); This method must be used to query t

Yii2 paging usage and its extension methods are described in detail, and yii2 paging extension is described in detail. Yii2 paging usage and its extension methods are described in detail, step by step teach you how to use the paging Yii2 page and how to expand it, yii2 page

The new features introduced in C #. NET Framewoke 3.0 provide extensions. NET class method , can increase the aesthetics of the Code!There are several requirements for writing an extension method:The class in which the extension method resides must be global, not an inner nested class, and the class of the extension method must be a static class .The

Use the extension functions provided by the JQuery library to implement custom methods and jquery extension Functions The JQuery package provides a large number of methods that can be directly used on the page. However, none of the libraries can meet all requirements. Therefore, the JQuery Library provides a wide range

: The extension method must be in a static class, and the class cannot be a nested class; The extension method must be static; The first parameter of an extension method must be the type to be extended, and the This keyword must be added; Extended properties, events are not supported. It is important to note that the

: The extension method must be in a static class, and the class cannot be a nested class; The extension method must be static; The first parameter of an extension method must be the type to be extended, and the This keyword must be added; Extended properties, events are not supported. It is important to note that the

Conditions for extension methods: must be declared as a static class must be declared as a static method the first parameter of a method is This first to expandUnitythe co-process inCoroutine,Using unityengine;using system.collections;using system;///again to expandTransformthe contents of the components, especially our relativex, y, zwhen assigning a value alone, it is more convenient to

(Var item in query) { Console.WriteLine (item. FirstName); } } 4. ThenByDescendingThe thenbydescending operator implements descending order of sequences by the secondary keyword. The query syntax for this operator is slightly different from the method syntax, as shown in the following code: using (NorthwindDataContext db = new northwinddatacontext ()) { //query syntax var query = From e in db. Employees E.firstname,e.lastname Descending Select E; //Method Syntax v

two times after using the order or orderbydescending efcontextnew efcontext (); var memberset = efmembercontext.set " role " var memberlist = Memberset.orderby (M = M.roleid). ThenByDescending (M => m.name); foreach (Member item in Memberlist) {Console.WriteLine ( Span> " {0},role:{1} " ,item. Name,item. Role.name);} If you want to sort more than one column in a database, you can first order (or orderbydescending) the ThenBy (or thenbydescending). You can also specify more than o

Original article:Http://blogs.msdn.com/csharpfaq/archive/2009/03/25/how-to-use-linq-methods-to-compare-objects-of-custom-types.aspx Translation:Http://www.cnblogs.com/tianfan/ LINQ provides a convenient syntax and incluuseful methods for operating with collections of objects. However, to be correctly processed by

Summary of the use of GroupBy Methods in LINQGroup is often used in SQL, usually to group a field or multiple fields, sum it up, mean value, etc.The GroupBy method in LINQ also has this capability. Specific implementation look at the code:Suppose that there is a dataset like the following:public class Studentscore {public int ID {set; get;} public string Name {set; get;} public string Course

element type if the index is exceeded var element_at_or_default_name = Names_array. Elementatordefault (5); var element_at_or_default_name2 = Names_array. Elementatordefault (ten); Console.WriteLine ("{0},{1}", Element_at_or_default_name, Element_at_or_ DEFAULT_NAME2); Console.WriteLine ("----------------------------"); Console.readkey ();Operation Result:All elements in the all sequence meet the criteriaWhether an element in the any seque

satisfies the condition, and returns the default value for the type if it is not foundListint index2 = users. FindIndex (3,5, u = u.age = = 22); Specifies the starting position and the end position, instead of the FindLastIndex ()ListUsers. Max (U = u.age); Users. Min (U = u.age); The smallest and the largestvar users6= users. GroupBy (U = u.gender). ToList (); Grouping, set of key-value pairs,ListUsers. RemoveAll (U = u.age Users. RemoveRange (2, 4); Deletes the specified number of elements st

//correct varWeldtable = ( fromTtinchdatabase. NdeweldingcheckdatawhereTt. Isdelete = =false TT. Fk_tascomid = =jobnoidSelectTT). (P=p.spatype). ThenBy (P=p.weldingchecktypegoup). ThenBy (P=p.ordernumber); //Error varWeldtable = ( fromTtinchdatabase. NdeweldingcheckdatawhereTt. Isdelete = =false TT. Fk_tascomid = =jobnoid byTT. Spatype, TT. Weldingchecktypegoup, TT. OrderNumberSelectTT); //Error varWeldtable = ( fromTtinchdatabase. NdeweldingcheckdatawhereTt. Isd

(extension) the prompt informationExtension methods that you might have used:If you've ever used LINQ, you'll find that the relationship between LINQ and extension methods is so close!So many blue arrows, hehe ....Some summary of

After the analysis of the previous two articles, we have learned the difference between the two implementations of Array.sort API Design On this issue, I have envisioned several API usage and design methods. For example, I initially wanted to use the "standard" extension method: Person[]　people　=　null; people 　　 .OrderBy(p　=>　p.Age)　//　指定主要排序规则 　　 .OrderBy(p　=>　p.ID,　true　/*　decending　*/)　//　指定次要排序规则 　　

;Gridview2.databind (); // Left joinVaR leftjoin = from Stu in db. StudentJoin SC in db. stucourseOn Stu. Sno equals SC. SnOInto tempFrom t in temp. defaultifempty ()Select New {Stu. Sno, Stu. Sage, cid = T = NULL? 0: T. CID };// Right joinVaR right = from SC in db. stucourseJoin Stu in db. StudentOn SC. Sno equals Stu. SnOInto tempFrom TT in temp. defaultifempty ()Select New {SC. CID, SC. Sno, sname = TT = NULL? "": TT. sname };// 5. Group of standard operators-groupby// Group by ageVaR stu6 =