WPF知识点备忘录——MVVM原理
通知类
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namespace WPFMVVM.ViewModels { class NotificationObject : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public void RasePropertyChanged(string propertyName) { this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } } }
命令类
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namespace WPFMVVM.Commands { class DelegateCommand : ICommand { public event EventHandler CanExecuteChanged; public bool CanExecute(object parameter) { if (CanExecuteFunc == null) return true; return this.CanExecuteFunc(parameter); } public void Execute(object parameter) { if (ExecuteAction == null) return; this.ExecuteAction(parameter); } public Action<object> ExecuteAction { get; set; } public Func<object,bool> CanExecuteFunc { get; set; } } }
View
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<Grid> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition/> <ColumnDefinition/> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Button Grid.Column="1" Grid.Row="1" HorizontalAlignment="Right" Content="Add" Command="{Binding AddCommand}"/> <Button Grid.Column="2" Grid.Row="1" HorizontalAlignment="Right" Content="Edit" Command="{Binding EditCommand}" CommandParameter="{Binding ElementName=dataGrid,Path=SelectedItem}"/> <DataGrid Grid.ColumnSpan="3" Name="dataGrid" Margin="3" Grid.Row="2" Padding="3" ItemsSource="{Binding People}" Grid.RowSpan="3" /> </Grid>
CS代码
public partial class BindingAndValidation : Window { public BindingAndValidation() { InitializeComponent(); this.DataContext = new BindingAndValidationViewModel(); } }
ViewModel
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namespace WPFMVVM.ViewModels { class BindingAndValidationViewModel : NotificationObject { private ObservableCollection<PersonModel> people = new ObservableCollection<PersonModel>(); public ICollection<PersonModel> People { get { return people; } set { people = (ObservableCollection<PersonModel>)value; this.RasePropertyChanged("People"); } } public DelegateCommand AddCommand { get; set; } public DelegateCommand DelCommand { get; set; } public DelegateCommand EditCommand { get; set; } private void Add(object parameter) { var dlg = new PersonEdit(null); if (dlg.ShowDialog() == true) { var mod = (PersonViewModel)dlg.DataContext; people.Add(new PersonModel { ID = mod.ID, Name = mod.Name }); } } private void Edit(object parameter) { var mod = (PersonModel)parameter; var dlg = new PersonEdit(mod); if (dlg.ShowDialog() == true) { var person = people.FirstOrDefault(x => x.ID == mod.ID); person.Name = mod.Name; } } public BindingAndValidationViewModel() { people.Add(new PersonModel { ID = 1, Name = "A" }); people.Add(new PersonModel { ID = 2, Name = "B" }); people.Add(new PersonModel { ID = 3, Name = "C" }); AddCommand = new DelegateCommand(); AddCommand.ExecuteAction = new Action<object>(this.Add); EditCommand = new DelegateCommand(); EditCommand.ExecuteAction = new Action<object>(this.Edit); } } }