РАЗРАБОТКА НА МНОГОСЛОЙНИ ПРИЛОЖЕНИЯЦветелин Павлов

План на курса

Обща информация, определенияСценарий за разработкаРазработка на базата данни и обектния домейнСъздаване на функционалностите за работа със студентски данни• Разработка на функционалностите за работа с оценки

МОДЕЛ НА ПРЕДМЕТНАТА ОБЛАСТ

Изходен код на проекта• Изтеглете: http://www.uni-ruse.bg/info-sys/lab-2.zip• Премахнете блокировката• Десен бутон -> Properties -> Unblock

• Разархивирайте• Премахнете ограничението „само за четене“• Отворете във Visual Studio• Разкачете проекта от системата за контрол на изходния код

Клас диаграма

Обектът „Оценка“Public Class Score Inherits DomainObject

Private ReadOnly theStudent As Student = Nothing Public ReadOnly Property Student As Student Get Return theStudent End Get End Property

Private theSubject As Subject Public Property Subject As Subject Get Return theSubject End Get Protected Set(value As Subject) theSubject = value End Set End Property

Public Property Value As Double

Public Sub New(aStudent As Student, aSubject As Subject, aValue As Double) theStudent = aStudent theSubject = aSubject Value = aValue End Sub

End Class

Обектът „Нова оценка“Public Class NewScore Inherits Score

Public Shadows Property Subject As Subject Get Return MyBase.Subject End Get Set(value As Subject) MyBase.Subject = value End Set End Property

Public Sub New(aStudent As Student) MyBase.New(aStudent, Nothing, 0) End Sub

End Class

УПРАЖНЕНИЕ № 2Създаване на функционалностите за работа със студентски данни

Скица на потребителския интерфейс

План на упражнението

• Шаблони за проектиране• Шаблонът „Model-View-ViewModel”• Разработка на модел• Разработка на модел на гледка за списъчен изглед• Разработка на списъчен изглед• Разработка на модел на гледка за редакция на студентски данни• Разработка на формуляр за редакция на студентски данни

Шаблони за проектиране

• a.k.a. Design patterns• Рецепти за проектиране• Независими от езика или платформата за програмиране• Най-известните: • Model-View-Controller – MVC• Adapter• Façade• Command• Abstract factory• Singleton

MVVM

MODELМоделът за връзка с базата данни

ILabDBAModelPublic Interface ILabDBAModel

Function GetStudents() As IList(Of Domain.Student) Function GetSubjects() As IList(Of Domain.Subject)

Sub SaveStudent(theStudent As Domain.Student) Sub SaveScore(theScore As Domain.Score)

Sub DeleteStudent(student As Domain.Student) Sub DeleteScore(score As Domain.Score)

End Interface

Entity Framework

Данни за връзка със сървъраСървър vader

Потребителско име InfoSys.Lab

Парола @Test-2012

Комбинация за свиване на кода

Ctrl + M, O

GetStudents Public Function GetStudents() As IList(Of Domain.Student) Implements ILabDBAModel.GetStudents Using orm As New InfoSysEntityModel(theConnectionString)

Dim dbResult As IList(Of Student) = orm.Students.ToList() Dim methodResult As New List(Of Domain.Student)()

For Each aStudent As Student In dbResult Dim translatedStudent As New Domain.Student(aStudent.StudentID)

translatedStudent.FirstName = aStudent.FirstName translatedStudent.LastName = aStudent.FamilyName translatedStudent.PhotoURL = aStudent.PhotoURL

Dim scores As List(Of Score) = aStudent.Scores.ToList() For Each Score As Score In scores Dim translatedSubject As New Domain.Subject(Score.Subject.SubjectName) Dim translatedScore As New Domain.Score(translatedStudent, translatedSubject, Score.Value) translatedStudent.Scores.Add(translatedScore) Next

methodResult.Add(translatedStudent) Next

Return methodResult End UsingEnd Function

Извличане на данни за студенти

Dim dbResult As IList(Of Student) = orm.Students.ToList()

SaveStudent Public Sub SaveStudent(theStudent As Domain.Student) Implements ILabDBAModel.SaveStudent Using orm As New InfoSysEntityModel(theConnectionString)

Dim aStudent As Student Dim isNew As Boolean = False

If TypeOf theStudent Is Domain.NewStudent Then aStudent = New Student() isNew = True Else aStudent = orm.Students.FirstOrDefault(Function(s) s.StudentID = theStudent.StudentID) isNew = False End If

aStudent.StudentID = theStudent.StudentID aStudent.FirstName = theStudent.FirstName aStudent.FamilyName = theStudent.LastName aStudent.PhotoURL = theStudent.PhotoURL

If isNew Then orm.Students.AddObject(aStudent) End If

orm.SaveChanges()

End UsingEnd Sub

Извличане на запис по ключ

aStudent = orm.Students.FirstOrDefault(Function(s) s.StudentID = theStudent.StudentID)

DeleteStudent Public Sub DeleteStudent(student As Domain.Student) Implements ILabDBAModel.DeleteStudent

Using orm As New InfoSysEntityModel(theConnectionString) Dim theStudent As Student = orm.Students.FirstOrDefault(Function(dbStudent) dbStudent.StudentID = student.StudentID)

If theStudent IsNot Nothing Then orm.Students.DeleteObject(theStudent) orm.SaveChanges() Else Throw New ObjectNotFoundException("Студент с такъв факултетен номер не е намерен в базата данни.") End If

End Using End Sub

СПИСЪК СТУДЕНТИИмплементиране на функционалностите за работа със списък от студенти

VIEW MODELМодел на списъчният изглед

Базов модел на гледкаImports System.ComponentModelImports InfoSys.Lab.Models

Public Class ViewModelBase Implements INotifyPropertyChanged

Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

Private ReadOnly theModel As ILabDBAModel Protected ReadOnly Property Model As ILabDBAModel Get Return theModel End Get End Property

Public Sub New(aModel As ILabDBAModel) theModel = aModel End Sub

Protected Sub DoNotify(aPropertyName As String) RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(aPropertyName)) End Sub

End Class

Модел на списъчната гледкаImports InfoSys.Lab.Domain

Public Interface IStudentsListViewModel

Property StudentsList As IList(Of Student) Property SelectedStudent As Student

ReadOnly Property RefreshStudentsListCommand As ICommand ReadOnly Property NewStudentCommand As ICommand ReadOnly Property DeleteStudentCommand As ICommand

End Interface

Свойството StudenstList

Public Property StudentsList As IList(Of Domain.Student) Implements IStudentsListViewModel.StudentsList Get Return theStudentsList End Get Set(value As IList(Of Domain.Student)) theStudentsList = value DoNotify("StudentsList") End SetEnd Property

Свойството SelectedStudent Public Property SelectedStudent As Domain.Student Implements IStudentsListViewModel.SelectedStudent Get Return theSelectedStudent End Get Set(value As Domain.Student) theSelectedStudent = value

DoNotify("SelectedStudent") DoNotify("IsSelected")

theMediator.SetStudent(theSelectedStudent) End SetEnd Property

Обработчици на командите

Private Sub whenRefresh() Me.StudentsList = Model.GetStudents()End Sub

Обработчици на командите

Private Function canDelete() As Boolean

Return IsSelected AndAlso Not TypeOf SelectedStudent Is NewStudent

End Function

Обработчици на командите

Private Sub whenDelete() If SelectedStudent IsNot Nothing Then Model.DeleteStudent(SelectedStudent) theMediator.DoRefresh() End IfEnd Sub

Обработчици на командите

Private Sub whenNew() Me.SelectedStudent = New NewStudent()End Sub

VIEWСписъчната гледка

Refresh бутон

<Button Command="{Binding Path=RefreshStudentsListCommand}" Content="Опресни" Margin="8" />

Бутон „Добавяне на студент“

<Button Command="{Binding Path=NewStudentCommand}" Content="Нов" Margin="8" Grid.Column="1" />

Бутон „Изтриване“

<Button Command="{Binding Path=DeleteStudentCommand}" Content="Изтрий" Margin="8" Grid.Column="2" />

Списъчна контрола

<ListBox ItemsSource="{Binding Path=StudentsList}" SelectedItem="{Binding Path=SelectedStudent, Mode=TwoWay}" Grid.ColumnSpan="3" Margin="8" Grid.Row="1" />

StudentsListView.xaml.vb

Public Class StudentsListView

Public Sub New(theVM As IStudentsListViewModel)

InitializeComponent() Me.DataContext = theVM

End Sub

End Class

Application.xaml.vbPrivate Sub WhenStart() Handles Me.Startup Dim theModel As New LabDBModel(“vader", "InfoSys.Lab.1", "InfoSys.Lab", "@Test-2012") Dim theMediator As New MainWindowMediator()

Dim theMainWindowViewModel As New MainWindowViewModel( Nothing, Nothing, Nothing, Nothing ) Dim theMainWindow As New MainWindow(theMainWindowViewModel)

theMainWindow.Show() Me.MainWindow = theMainWindow End Sub

Бази данни

InfoSys.Lab.DB.1-1...

InfoSys.Lab.DB.3-9

Добавяне на списъчната гледка

Dim theStudenstListViewModel As New StudentsListViewModel( theModel, theMediator)

theMediator.RegisterCanRefresh(theStudenstListViewModel)

Dim theStudentsListView As New StudentsListView( theStudenstListViewModel)

Инжектиране в основния прозорец

Dim theMainWindowViewModel As New MainWindowViewModel (

Nothing, Nothing, Nothing, theStudentsListView

)

РЕДАКЦИЯ НА СТУДЕНТИмплементиране на функционалностите за редакция на информацията на студент

VIEW MODELМодел на формуляра

Модел на формуляраImports InfoSys.Lab.Domain

Public Interface IStudentEditViewModel

Property StudentID As String

Property FirstName As String Property LastName As String

Property PhotoURL As String

ReadOnly Property isNew As Boolean Property isChanged As Boolean

ReadOnly Property SaveStudent As ICommand

End Interface

Свойството StudentProtected Property Student As Domain.Student Get Return theStudent End Get Set(value As Domain.Student) theStudent = value isChanged = False

DoNotify("FirstName") DoNotify("LastName") DoNotify("StudentID") DoNotify("PhotoURL") DoNotify("isNew") DoNotify("IsSelected") End SetEnd Property

Обработчици на командите

Private Sub WhenSaveStudent() Model.SaveStudent(Student) theMediator.DoRefresh()End Sub

VIEWГледка на формуляра

Етикети

<Label Content="Факултетен номер" Margin="8"/><Label Content="Собствено име" Margin="8" Grid.Row="1"/><Label Content="Фамилия" Margin="8" Grid.Row="2"/>

Поле за факултетен номер

<TextBox Text="{Binding Path=StudentID, Mode=TwoWay}" IsEnabled="{Binding Path=isNew}" Grid.Column="1" Margin="8" TextWrapping="Wrap" MinWidth="60" />

Поле за собствено име

<TextBox Text="{Binding Path=FirstName, Mode=TwoWay}" Grid.Column="1" Margin="8" TextWrapping="Wrap" Grid.Row="1" Grid.ColumnSpan="2" />

Поле за фамилия

<TextBox Text="{Binding Path=LastName, Mode=TwoWay}" Grid.Column="1" Margin="8" TextWrapping="Wrap" Grid.Row="2" Grid.ColumnSpan="2" />

Бутон за запазване

<Button Command="{Binding Path=SaveStudent}" IsEnabled="{Binding Path=isChanged}" Content="Запази" Grid.Column="2" Grid.Row="3" Margin="8" VerticalAlignment="Top" />

StudentEditView.xaml.vb

Public Class StudentEditView

Public Sub New(theVM As IStudentEditViewModel)

InitializeComponent() Me.DataContext = theVM

End Sub

End Class

Application.xaml.vbDim theStudentEditViewModel As New StudentEditViewModel( theModel, theMediator)

theMediator.RegisterInterestedInStudent( theStudentEditViewModel)

Dim theStudentEditView As New StudentEditView( theStudentEditViewModel)

Инжектиране в основния прозорец

Dim theMainWindowViewModel As New MainWindowViewModel (

Nothing, Nothing, theStudentEditView, theStudentsListView

)

КРАЙ НА УПРАЖНЕНИЕ № 2Създаване на функционалностите за работа със студентски данни