模板
教程
環境
性能
功能
管理
軟件測試 > 測試開發技術 > 軟件測試開發語言 > 數據庫 > SQL Server >
LINQ基本操作
首先我們創建2個類，一個Category，一個Product public class Product{ public string Name { get ; set ; } public int CategoryID { get ; set ; }} public class Category{ public string Name { get ; set ; } public int ID { get ; set ; }} 然后創建2
首先我們創建2個類，一個Category，一個Productpublic class Product { public string Name { get; set; } public int CategoryID { get; set; } } public class Category { public string Name { get; set; } public int ID { get; set; } }
static List<Category> categories = new List<Category>() { new Category(){Name="Beverages", ID=001}, new Category(){Name="Condiments", ID=002}, new Category(){Name="Vegetables", ID=003}, new Category(){Name="Grains", ID=004}, new Category(){Name="Fruit", ID=005}, new Category(){Name="Other", ID=006} }; static List<Product> products = new List<Product>() { new Product{Name="Cola", CategoryID=001}, new Product{Name="Tea", CategoryID=001}, new Product{Name="Mustard", CategoryID=002}, new Product{Name="Pickles", CategoryID=002}, new Product{Name="Carrots", CategoryID=003}, new Product{Name="Bok Choy", CategoryID=003}, new Product{Name="Peaches", CategoryID=005}, new Product{Name="Melons", CategoryID=007}, };
l 使用排序
1. 使用排序時使用的顯示語句
foreach (var c in orderByResult) Console.WriteLine("ID={0},Name={1}", c.ID, c.Name);
表達式
var orderByResult = from c in categories orderby c.ID //默認為升序，也可以在后面加上ascending select c; // 方法 var orderByResult = categories.OrderBy(c=>c.ID);
表達式
var orderByResult = from c in categories orderby c.ID descending select c; // 方法 var orderByResult = categories.OrderByDescending(c=>c.ID);
4. 多個屬性的升序
表達式
var orderByResult = from c in categories orderby c.ID,c.Name select c; //方法 var orderByResult = categories.OrderBy(c=>c.ID).ThenBy(c=>c.Name);
表達式
var orderByResult = from c in categories orderby c.ID, c.Name descending select c; //方法 var orderByResult = categories.OrderByDescending(c=>c.ID).ThenByDescending(c=>c.Name);
