摘要： Projecting - Select//1、Select-Subqueries and Object Hierarchiesstring sampleDirectory = Environment.GetFolderPath (Environment.SpecialFolder.MyDocuments); DirectoryInfo[] dirs = new DirectoryInfo (sampleDirectory).GetDirectories(); var query = from d in dirs where (d.Attributes & FileAttributes. 阅读全文

摘要： Filtering//1、Simple Local Filterstring[] names = { "Tom", "Dick", "Harry", "Mary", "Jay" }; IEnumerable<string> query = names.Where (name => name.EndsWith ("y")); query.Dump ("In lambda syntax"); query = from n in names w 阅读全文

摘要： Building Query Expressions//1、Compiling Expression TreesProducts.DeleteAllOnSubmit (Products.Where (p => p.ID == 999));Products.InsertOnSubmit (new Product { ID = 999, Description = "Test", LastSale = DateTime.Now } );SubmitChanges();Product[] localProducts = Products.ToArray();Expressi 阅读全文

摘要： //LINQ to SQL//1、Baisc queryCustomers.Single (c => c.ID == 2) .Dump ("Customer With ID Of 2");//2、AssociationsCustomer cust1 = Customers.OrderBy (c => c.Name).First();foreach (Purchase p In cust1.Purchases)Console.WriteLine (p.Price);//3、 Retrieve the customer who made the lowest val 阅读全文

摘要： APPLY的执行过程：它先逻辑计算左表表达式，然后把右表达式应用到左表表达式的每一行。cross tb表都存在姓名的情况下才出现,outer tb外表存在的都显示。 create table #T(姓名 varchar(10))insert into #T values('张三')insert into #T values('李四')insert into #T values(NULL )crea... 阅读全文

摘要： Interpreted Queries//1、Simple LINQ to SQL Queryfrom c in Customerswhere c.Name.Contains ("a")orderby c.Name.Lengthselect c.Name.ToUpper()//2、Combining Interpreted and Local Queriesvoid Main(){//This uses a custom 'Pair' extension method, defined below.IEnumerable<string> q = 阅读全文

摘要： //Deferred Execution//1、Introductionvar numbers = new List<int>();numbers.Add (1); //10IEnumerable<int> query = numbers.Select (n => n * 10);// Build querynumbers.Add (2); //20 // Sneak in a... 阅读全文

摘要： use Nutshellif exists (select * from sysobjects where name = 'PurchaseItem') drop table PurchaseItemif exists (select * from sysobjects where name = 'Purchase') drop table Purchaseif exists (select *... 阅读全文

摘要： 推荐一个Linq学习工具：LinqPad 网址：http://www.linqpad.net/ 下载: for .net 3.5:http://www.linqpad.net/GetFile.aspx?LINQPad.exe for .net 4.0:http://www.linqpad.net/GetFile.aspx?LINQPad4.zip //1、Now for a simp... 阅读全文

摘要： 使用ContentProvider共享数据ContentProvider类主要方法的作用：public boolean onCreate()该方法在ContentProvider创建后就会被调用， Android在系统启动时就会创建ContentProvider 。public Uri insert(Uri uri, ContentValues values)该方法用于供外部应用往ContentProvider添加数据。public int delete(Uri uri, String selection, String[] selectionArgs)该方法用于供外部应用从ContentPr 阅读全文