C# EF 使用

WPF EF MySQL

- - -	版本
.NET Framework	4.7.2
EntityFramework	6.5.1
MySql.Data.EntityFramework	9.1.0

• 创建数据库 cc
• App.config

<connectionStrings><add name="MyDbContext" providerName="MySql.Data.MySqlClient" connectionString="server=127.0.0.1;port=3306;database=cc;user=root;password=123456;persistsecurityinfo = True;Character Set=utf8;" />
</connectionStrings>
<system.data><DbProviderFactories><remove invariant="MySql.Data.MySqlClient"/><add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=9.1.0.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"/></DbProviderFactories>
</system.data>

• 测试

public partial class MainWindow : Window
{public MainWindow(){InitializeComponent();try{using (var context = new MyDbContext()){ // 查询var entities = context.MyEntities.Where(e => e.Name == "example").ToList();// 添加var newEntity = new MyEntity { Name = "new example" };context.MyEntities.Add(newEntity);context.SaveChanges();// 更新//var existingEntity = context.MyEntities.Find(newEntity.Id);//existingEntity.Name = "updated example";//context.SaveChanges();// 删除// context.MyEntities.Remove(existingEntity);//context.SaveChanges();}}catch (Exception ex){var d = "";}}
}[DbConfigurationType(typeof(MySql.Data.EntityFramework.MySqlEFConfiguration))]
public class MyDbContext : DbContext
{public MyDbContext() : base("name=MyDbContext"){ } public DbSet<MyEntity> MyEntities { get; set; }
}[Table("my_table")]
public class MyEntity
{[Key][DatabaseGenerated(DatabaseGeneratedOption.Identity)]public int Id { get; set; }[Required][StringLength(100)]public string Name { get; set; }
}

• 打开 NuGet 包管理器控制台

Enable-Migrations -Force # 会在跟目录生成 Migrations\Configuration.cs
AutomaticMigrationsEnabled = true;  # Configuration.cs 中修改
update-database -Force	# 迁移

Enable-Migrations [-ContextTypeName <String>] [-EnableAutomaticMigrations] [-ProjectName <String>] [-StartUpProjectName <String>] [-ConnectionStringName <String>] [-Force] [<CommonParameters>]
ContextTypeName：项目继承自DBContext的类名字。
EnableAutomaticMigrations：开启自动迁移。
ProjectName：存放DBContext类的项目名称。
StartUpProjectName：解决方案中启动项目的名称，作用是调用该项目下的连接字符串。
ConnectionStringName：连接字符串名称Enable-Migrations -ContextTypeName "WpfApp2.MyDbContext" -ProjectName "WpfApp2" -StartUpProjectName "WpfApp2" -ConnectionStringName "MyDbContext" -Verbose -Force
update-database  -ProjectName "WpfApp2" -StartUpProjectName "WpfApp2" -ConnectionStringName "MyDbContext"  -Verbose -Force

WPF EF SQLServer

- - -	版本
.NET Framework	4.7.2
EntityFramework	6.5.1

• 创建数据库 cc
• App.config

<connectionStrings><add name="MyDbContext" providerName="System.Data.SqlClient" connectionString="data source=LAPTOP-EGHJ2RO7;initial catalog=t1;user id=sa;password=1234567;connection timeout=5" />
</connectionStrings>

• 测试

public partial class MainWindow : Window
{public MainWindow(){InitializeComponent();try{using (var context = new MyDbContext()){ // 查询var entities = context.MyEntities.Where(e => e.Name == "example").ToList();// 添加var newEntity = new MyEntity { Name = "new example" };context.MyEntities.Add(newEntity);context.SaveChanges();// 更新//var existingEntity = context.MyEntities.Find(newEntity.Id);//existingEntity.Name = "updated example";//context.SaveChanges();// 删除// context.MyEntities.Remove(existingEntity);//context.SaveChanges();}}catch (Exception ex){var d = "";}}
}public class MyDbContext : DbContext
{public MyDbContext() : base("name=MyDbContext"){ } public DbSet<MyEntity> MyEntities { get; set; }
}[Table("my_table")]
public class MyEntity
{[Key][DatabaseGenerated(DatabaseGeneratedOption.Identity)]public int Id { get; set; }[Required][StringLength(100)]public string Name { get; set; }
}

• 打开 NuGet 包管理器控制台

Enable-Migrations -Force # 会在跟目录生成 Migrations\Configuration.cs
AutomaticMigrationsEnabled = true;  # Configuration.cs 中修改
update-database -Force	# 迁移

Enable-Migrations [-ContextTypeName <String>] [-EnableAutomaticMigrations] [-ProjectName <String>] [-StartUpProjectName <String>] [-ConnectionStringName <String>] [-Force] [<CommonParameters>]
ContextTypeName：项目继承自DBContext的类名字。
EnableAutomaticMigrations：开启自动迁移。
ProjectName：存放DBContext类的项目名称。
StartUpProjectName：解决方案中启动项目的名称，作用是调用该项目下的连接字符串。
ConnectionStringName：连接字符串名称Enable-Migrations -ContextTypeName "WpfApp2.MyDbContext" -ProjectName "WpfApp2" -StartUpProjectName "WpfApp2" -ConnectionStringName "MyDbContext" -Verbose -Force
update-database  -ProjectName "WpfApp2" -StartUpProjectName "WpfApp2" -ConnectionStringName "MyDbContext"  -Verbose -Force