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操作本地数据库

2020-11-09 15:32:51 责编:小采

1.创建实体注意加Table和Column特性 /// summary /// 课程类 /// /summary [Table] //表示类将成为一个table public class Course : INotifyPropertyChanged, INotifyPropertyChanging { [Column(IsVersion = true)] //table的列 private Binary _version;

1.创建实体注意加Table和Column特性

 /// 
 /// 课程类
 /// 
 [Table] //表示类将成为一个table
 public class Course : INotifyPropertyChanged, INotifyPropertyChanging
 {
 [Column(IsVersion = true)] //table的列
 private Binary _version;

 private int _id;
 [Column(IsPrimaryKey=true,IsDbGenerated=true)] //table的列，主键，自动生成
 public int Id
 {
 get { return _id; }
 set 
 {
 if (_id != value)
 {
 RaiseProtertyChanging("Id");
 _id = value;
 RaisePropertyChanged("Id");
 }
 }
 }

 private string _name;
 [Column]
 public string Name
 {
 get { return _name; }
 set
 {
 if (_name != value)
 {
 RaiseProtertyChanging("Name");
 _name = value;
 RaisePropertyChanged("Name");
 }
 }
 }

 private string _location;
 [Column]
 public string Location
 {
 get { return _location; }
 set
 {
 if (_location != value)
 {
 RaiseProtertyChanging("Location");
 _location = value;
 RaisePropertyChanged("Location");
 }
 }
 }

 public event PropertyChangedEventHandler PropertyChanged;

 private void RaisePropertyChanged(string propertyName)
 {
 if (PropertyChanged != null)
 {
 PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
 }
 }

 public event PropertyChangingEventHandler PropertyChanging;

 private void RaiseProtertyChanging(string propertyName)
 {
 if (PropertyChanging != null)
 {
 PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
 }
 }
 }

2.创建类继承DataContext,而且封装this.GetTable()方法,否则创建数据库时报错

 public class MyDataContext : DataContext
 {
 //连接字符窜
 public const string ConnectionString = "Data Source=isostore:/MyDb.sdf";

 //构造函数
 public MyDataContext()
 : base(ConnectionString)
 {
 if (!this.DatabaseExists())
 {
 //创建数据库
 this.CreateDatabase();
 }
 }
 //必须存在，否则创建数据库报错：DataContext不存在表
 public Table CourseTable
 {
 get { return this.GetTable(); }
 }
 }

3.页面前台代码

4.页面后台代码

添加：调用GetTable().InsertOnSubmit(T)方法，最后调用SubmitChanges()向数据库提交数据。

删除: GetTable().DeleteOnSubmit(T)方法，最后调用SubmitChanges()向数据库提交数据。

编辑：调用SubmitChanges()

页面绑定的数据源必须是ObservableCollection类型

 public partial class MainPage : PhoneApplicationPage
 {
 private ObservableCollection Courses;
 private DataContext _data;
 // 构造函数
 public MainPage()
 {
 InitializeComponent();
 //创建数据库
 //CreateDatabase();
 _data = new MyDataContext();
 //初始化数据
 InitData();
 }

 private void CreateDatabase()
 {
 _data = new MyDataContext();
 if (!_data.DatabaseExists())
 {
 _data.CreateDatabase();
 }
 }

 private void InitData()
 {
 Courses = new ObservableCollection
 {
 new Course{Name="电子商务",Location="教学楼101"},
 new Course{Name="心理学",Location="教学楼101"},
 new Course{Name="高等数学",Location="教学楼101"},
 new Course{Name="网络营销",Location="教学楼101"},
 };
 foreach (var c in Courses)
 {
 _data.GetTable().InsertOnSubmit(c);//插入数据库
 }
 _data.SubmitChanges();
 this.CourseList.ItemsSource = Courses;
 
 }
 //添加事件
 private void Button_Click(object sender, RoutedEventArgs e)
 {
 Course c = new Course()
 {
 Name = "客户关系管理",
 Location = "教学楼401"
 };
 Courses.Add(c);
 _data.GetTable().InsertOnSubmit(c);
 _data.SubmitChanges();
 }
 //编辑事件
 private void Button_Click_1(object sender, RoutedEventArgs e)
 {
 Course c = Courses.First(s => s.Name == "网络营销");
 c.Location = "编辑教学楼";
 _data.SubmitChanges();
 
 }
 //删除事件
 private void Button_Click_2(object sender, RoutedEventArgs e)
 {
 Course c = Courses.First(s => s.Name == "电子商务");
 Courses.Remove(c);
 _data.GetTable().DeleteOnSubmit(c);
 _data.SubmitChanges();
 }
 }

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