Operate a local database

1. When creating an object, pay attention to adding the Table and Column features. The summary course class summary [Table] indicates that the class will become a tablepublicclassCourse: INotifyPropertyChanged, INotifyPropertyChanging {[Column (IsVersiontrue)] table Column privat;

1. when creating an object, note that adding the Table and Column features // summary // Course class // summary [Table] // indicates that the class will become a table public class Course: INotifyPropertyChanged, INotifyPropertyChanging {[Column (IsVersion = true)] // private Binary _ version of the table Column;

1. Add the Table and Column features to create objects.

////// Course type ///   [Table]// Indicates that the class will become a table public class Course: INotifyPropertyChanged, INotifyPropertyChanging {[Column (IsVersion = true)]// Private Binary _ version; private int _ id;[Column (IsPrimaryKey = true, IsDbGenerated = true)] // table Column, primary key, automatically generatedPublic 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. Create a class that inherits DataContext and encapsulates this. GetTable () Method. Otherwise, an error is returned when you create a database.

Public class MyDataContext: DataContext {// connection character public const string ConnectionString = "Data Source = isostore:/MyDb. sdf "; // constructor public MyDataContext (): base (ConnectionString) {if (! This. DatabaseExists () {// create the database this. CreateDatabase ();}}// It must exist; otherwise, the database creation error is returned: DataContext does not exist Table public Table
  
   
CourseTable {get {return this. GetTable
   
    
();}}
   
  }

3. Page front-end code

4. Page background code

Add: Call GetTable (). InsertOnSubmit (T) method, and finally call SubmitChanges () to submit data to the database.

Delete: GetTable (). DeleteOnSubmit (T) method, and finally call SubmitChanges () to submit data to the database.

Edit: Call SubmitChanges ()

The data source bound to the page must beObservableCollection type

Public partial class MainPage: PhoneApplicationPage {Private ObservableCollection
  
   
Courses;
  Private DataContext _ data; // constructor public MainPage () {InitializeComponent (); // create a database // CreateDatabase (); _ data = new MyDataContext (); // initialize the data InitData ();} private void CreateDatabase () {_ data = new MyDataContext (); if (! _ Data. DatabaseExists () {_ data. CreateDatabase () ;}} private void InitData () {Courses = new ObservableCollection
 
  
{New Course {Name = "e-commerce", Location = "teaching building 101"}, new Course {Name = "Psychology", Location = "teaching building 101 "}, new Course {Name = "Advanced Mathematics", Location = "teaching building 101"}, new Course {Name = "network marketing", Location = "teaching building 101 "},}; foreach (var c in Courses ){
  _ Data. GetTable
   
    
(). InsertOnSubmit (c); // insert a database
   }
  _ Data. SubmitChanges (); this. CourseList. ItemsSource = Courses;} // Add event private void Button_Click (object sender, RoutedEventArgs e) {Course c = new Course () {Name = "Customer Relationship Management", Location = "teaching building 401 "}; courses. add (c );
  _ Data. GetTable
   
    
(). InsertOnSubmit (c); _ data. SubmitChanges ();
   } // Edit event private void Button_Click_1 (object sender, RoutedEventArgs e) {Course c = Courses. first (s => s. name = "network marketing"); c. location = "Edit teaching building ";
  _ Data. SubmitChanges ();} // Delete the event private void Button_Click_2 (object sender, RoutedEventArgs e) {Course c = Courses. first (s => s. name = "e-commerce"); Courses. remove (c );
  _ Data. GetTable
   
    
(). DeleteOnSubmit (c); _ data. SubmitChanges ();
   }}