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- 本文详细介绍了SQLite实现CodeFirst的方式
- 通过代码配合图文的形式进行讲解
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本文所介绍的是真正的EF+CodeFirst，不需要提前建表，由代码自动生成！
一、提前准备
1 下载Sqlite Expert
下载免费版个人版就够用了
- 下载后新建数据库，然后保存到你指定的目录即可（保存为.db文件）
2 安装VS扩展工具
- 然后在VS中->工具->扩展和更新->联机
- 搜索SQLite/SQL Server Compact ToolBox ，下载完后重启VS
- 在同一个地方再搜索dotConnect ADO.NET Data Provider for SQLite，记得不是安装Standard的，点下载后会出现个弹出框下载，下载完后安装时要先关闭VS
二、项目接入
1 先在NuGet中添加相关依赖项
- SQLite和SQLite.CodeFirst
2 定义实体类
public class Student
{
public int ID { get; set; }
public string Name { get; set; }
public int Age { get; set; }
public string Gender { get; set; }
}3 添加Context类
- 继承自DbContext以及Model配置类
public class StudentContext : DbContext
{
//定义属性，便于外部访问数据表
public DbSet<Student> Students { get { return Set<Student>(); } }
public StudentContext() : base("dbConn")
{
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
ModelConfiguration.Configure(modelBuilder);
var init = new SqliteDropCreateDatabaseWhenModelChanges<StudentContext>(modelBuilder);
//var init = new SqliteCreateDatabaseIfNotExists<MyBookDB>(modelBuilder);
Database.SetInitializer(init);
}
}
public class ModelConfiguration
{
public static void Configure(DbModelBuilder modelBuilder)
{
ConfigureBookEntity(modelBuilder);
}
private static void ConfigureBookEntity(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>();
}
}4 获取数据库连接字符串
- 工具->连接到数据库->更改->选择SQLite Database->Browse数据库文件->测试成功后复制Connection String
5 修改配置文件APP.config
- 在</system.data>结点后面添加连接字符串
<connectionStrings>
<add name="SQLiteConnect" connectionString="Data Source=F:\xxx\SQLLiteTest.db" providerName="System.Data.SQLite.EF6"/>
</connectionStrings>- 添加Provider结点（主要原因是SQLite的invarianName不是在自动生成的.EF6里面）
<provider invariantName="System.Data.SQLite" type="System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6" />
三、验证测试
1 界面窗口布局
2 按钮事件
private void btnAdd_Click(object sender, EventArgs e)
{
List<Student> books = new List<Student>()
{
new Student() {ID=1, Name = "小明", Age = 11, Gender = "男" },
new Student() {ID=2, Name = "老王", Age = 12, Gender = "男" },
new Student() {ID=3, Name = "小郭", Age = 10, Gender = "女" },
new Student() {ID=4, Name = "小李", Age = 11, Gender = "男" },
new Student() {ID=5, Name = "小玉", Age = 9, Gender = "女" },
};
using (var db = new StudentContext())
{
db.Students.AddRange(books);
int count = db.SaveChanges();
this.Text = $"{DateTime.Now}, 插入{count}条记录";
}
}
private void btnModify_Click(object sender, EventArgs e)
{
using (var db = new StudentContext())
{
var students = db.Students.FirstOrDefault(x => x.Name == "小李");
if (students != null)
{
students.Age += 1;
int count = db.SaveChanges();
this.Text = $"{DateTime.Now}, 修改{count}条记录";
}
}
}
private void btnDel_Click(object sender, EventArgs e)
{
using (var db = new StudentContext())
{
var students = db.Students.FirstOrDefault(x => x.Name == "小玉");
if (students != null)
{
var result = db.Students.Remove(students);
int count = db.SaveChanges();
this.Text = $"{DateTime.Now}, 删除{count}条记录";
}
}
}
private void btnQuery_Click(object sender, EventArgs e)
{
using (var db = new StudentContext())
{
var students = db.Students.Where(x => x.Name == "老王").OrderByDescending(x => x.Age).ToList();
this.Text = $"{DateTime.Now}, 查到{students.Count}条记录";
this.dataGridView1.DataSource = students;
}
}
private void btnRefresh_Click(object sender, EventArgs e)
{
using (var db = new StudentContext())
{
var students = db.Students.ToList();
this.dataGridView1.DataSource = students;
}
}3 效果
- 根据代码生成表
