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Bài giới thiệu nhanh về mô hình kiến trúc phần mềm MVVM (Model-View-ViewModel).
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Software Architecture Pattern
M-V-VM(Model-View-ViewModel)
Friday, July 26, 2013
View
ViewModel
Commands
Data
Binding
Model
Model
public class Person{
public Person() { }public string FirstName { get; set; }public string LastName { get; set; }public string Age { get; set; }
}
ViewModel
public class MainViewModel : INotifyPropertyChanged{
public event PropertyChangedEventHandler PropertyChanged;private void NotifyPropertyChanged(String propertyName){
PropertyChangedEventHandler handler = PropertyChanged;if (null != handler){
handler(this, new PropertyChangedEventArgs(propertyName));}
}}
ViewModel
private Person _selectedPerson;public Person SelectedPerson{
get { return _selectedPerson; }set{
if (_selectedPerson != value) {_selectedPerson = value;NotifyPropertyChanged("SelectedPerson");
}}
}
View
<TextBox Text="{Binding FirstName, Mode=TwoWay}" />
View
<ListViewItemsSource="{Binding ListOfPerson}"SelectedItem="{Binding SelectedPerson, Mode=TwoWay}" />
View
ViewModel
Commands
Data
Binding
Model
• The Mode property determines how changes are synchronized
between the target control and data source– OneTime – Control property is set once to the data value and any subsequent changes
are ignored
– OneWay – Changes in the data object are synchronized to the control property, but
changes in the control are not synchronized back to the data object
– TwoWay – Changes in the data object are synchronized to the control property and vice-
versa
<TextBlock x:Name="FirstName" Text="{Binding FirstName, Mode=OneWay}"/>
• ViewModels implement INotifyPropertyChanged
public class ProfileViewModel : INotifyPropertyChanged{
private Person _person;public Person Person{
get { return _person; }set {
if (value != _person){_person = value;NotifyPropertyChanged("Person");
}}
}
public event PropertyChangedEventHandler PropertyChanged;private void NotifyPropertyChanged(String propertyName){
if (null != PropertyChanged) PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}}
<Button Command="{Binding EditCommand}"
CommandParameter="{Binding SelectedPerson}"
Content="Edit" HorizontalAlignment="Center"
VerticalAlignment="Center"/>
class EditPersonCommand : ICommand
{
ViewModel _viewModel;
public EditPersonCommand(ViewModel viewModel)
{
_viewModel = viewModel;
}
public event EventHandler CanExecuteChanged;
public bool CanExecute(object parameter)
{
return true;
}
public void Execute(object person)
{
_viewModel.EditPerson(person as Person);
}
}
• Reuse Model and View-Model code
• Test the ViewModel with unit tests
• Maintainability
• Can show design-time data in Expression
Blend and the Visual Studio designer
http://caliburnmicro.codeplex.com/http://mvvmlight.codeplex.com/
Rob EisenbergLaurent Bugnion
http://msdn.microsoft.com/en-us/library/gg405484%28v=pandp.40%29.aspx
http://msdn.microsoft.com/en-us/magazine/jj651572.aspx
Software Architecture Design
M-V-VM(Model-View-ViewModel)
18/07/2013
