• Dapper.NET使用
• 1、为什么选择Dapper
• 2、以Dapper（4.0）为例。
• 2.1 在数据库中建立几张表。
• 2.2实体类。
• 3.使用方法
• 3.1  一对一映射
• 3.2 一对多映射
• 3.3 插入实体
• 3.4 执行存储过程

CREATE TABLE [dbo].[CICUser]
([UserId]                [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,[Username]              [nvarchar](256) NOT NULL,[PasswordHash]          [nvarchar](500) NULL,[Email]                 [nvarchar](256) NULL,[PhoneNumber]           [nvarchar](30) NULL,[IsFirstTimeLogin]      [bit] DEFAULT(1) NOT NULL,[AccessFailedCount]     [int] DEFAULT(0) NOT NULL,[CreationDate]          [datetime] DEFAULT(GETDATE()) NOT NULL,[IsActive]              [bit] DEFAULT(1) NOT NULL
)CREATE TABLE [dbo].[CICRole]
([RoleId]       [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,[RoleName]     [nvarchar](256) NOT NULL,
)CREATE TABLE [dbo].[CICUserRole]
([Id]   [int] IDENTITY(1, 1) PRIMARY KEY NOT NULL,[UserId]  [int] FOREIGN KEY REFERENCES [dbo].[CICUser] ([UserId]) NOT NULL,[RoleId]  [int] FOREIGN KEY REFERENCES [dbo].[CICRole] ([RoleId]) NOT NULL
)

public class User
{public User(){Role = new List<Role>();}public int UserId { get; set; }public string UserName { get; set; }       public string Password { get; set; }public string Email { get; set; }public string PhoneNumber { get; set; }public bool IsFirstTimeLogin { get; set; }public int AccessFailedCount { get; set; }public DateTime CreationDate { get; set; }public bool IsActive { get; set; }public List<Role> Role { get; set; }
}
public class Role
{public int RoleId { get; set; }public string RoleName { get; set; }
}
public class Customer
{public int UserId { get; set; }public string UserName { get; set; }       public string Password { get; set; }public string Email { get; set; }public string PhoneNumber { get; set; }public bool IsFirstTimeLogin { get; set; }public int AccessFailedCount { get; set; }public DateTime CreationDate { get; set; }public bool IsActive { get; set; }public Role Role { get; set; }
}    

private static void OneToOne(string sqlConnectionString)
{List<Customer> userList = new List<Customer>();using (IDbConnection conn = GetSqlConnection(sqlConnectionString)){string sqlCommandText = @"SELECT c.UserId,c.Username AS UserName,c.PasswordHash AS [Password],c.Email,c.PhoneNumber,c.IsFirstTimeLogin,c.AccessFailedCount,c.CreationDate,c.IsActive,r.RoleId,r.RoleName FROM dbo.CICUser c WITH(NOLOCK) INNER JOIN CICUserRole cr ON cr.UserId = c.UserId INNER JOIN CICRole r ON r.RoleId = cr.RoleId";userList = conn.Query<Customer, Role, Customer>(sqlCommandText, (user, role) => { user.Role = role; return user; },null,null,true, "RoleId", null,null).ToList();}if (userList.Count > 0){userList.ForEach((item) => Console.WriteLine("UserName:" + item.UserName +"----Password:" + item.Password + "-----Role:" + item.Role.RoleName +"\n"));Console.ReadLine();}
}

private static void OneToMany(string sqlConnectionString)
{Console.WriteLine("One To Many");List<User> userList = new List<User>();using (IDbConnection connection = GetSqlConnection(sqlConnectionString)){string sqlCommandText3 = @"SELECT c.UserId,c.Username      AS UserName,c.PasswordHash  AS [Password],c.Email,c.PhoneNumber,c.IsFirstTimeLogin,c.AccessFailedCount,c.CreationDate,c.IsActive,r.RoleId,r.RoleNameFROM   dbo.CICUser c WITH(NOLOCK)LEFT JOIN CICUserRole crON  cr.UserId = c.UserIdLEFT JOIN CICRole rON  r.RoleId = cr.RoleId";var lookUp = new Dictionary<int, User>();userList = connection.Query<User, Role, User>(sqlCommandText3,(user, role) =>{User u;if (!lookUp.TryGetValue(user.UserId, out u)){lookUp.Add(user.UserId, u = user);}u.Role.Add(role);return user;}, null, null, true, "RoleId", null, null).ToList();var result = lookUp.Values;}if (userList.Count > 0){userList.ForEach((item) => Console.WriteLine("UserName:" + item.UserName +"----Password:" + item.Password +"-----Role:" + item.Role.First().RoleName +"\n"));Console.ReadLine();}else{Console.WriteLine("No Data In UserList!");}
}

public static void InsertObject(string sqlConnectionString)
{string sqlCommandText = @"INSERT INTO CICUser(Username,PasswordHash,Email,PhoneNumber) VALUES (@UserName,@Password,@Email,@PhoneNumber)";using (IDbConnection conn = GetSqlConnection(sqlConnectionString)){User user = new User();user.UserName = "Dapper";user.Password = "654321";user.Email = "Dapper@infosys.com";user.PhoneNumber = "13795666243";int result = conn.Execute(sqlCommandText, user);if (result > 0){Console.WriteLine("Data have already inserted into DB!");}else{Console.WriteLine("Insert Failed!");}Console.ReadLine();}
}