WPF：实现MVVM按钮命令

Posted 2023-01-20

所以我有qazxsw poi应用程序与主窗口和2 qazxsw poi：

1. WPF
2. UserControls

查看模型

HomeView.xaml

Whan申请开始

OptionsView.xaml

Windows资源

public class ApplicationViewModel : INotifyPropertyChanged
    
        #region Fields

        private ICommand changePageCommand;
        private ICommand addFilesCommand;
        private IPageViewModel _currentPageViewModel;
        private List<IPageViewModel> _pageViewModels;
        #endregion

        public ApplicationViewModel()
        
            // Add available pages
            PageViewModels.Add(new HomeViewModel()  IsSelected = true );
            PageViewModels.Add(new OptionsViewModel()  IsSelected = false );

            // Set starting page
            CurrentPageViewModel = PageViewModels[0];
        

        #region Properties / Commands

        public ICommand ChangePageCommand
        
            get
            
                if (changePageCommand == null)
                
                    changePageCommand = new RelayCommand(
                        p => ChangeViewModel((IPageViewModel)p),
                        p => p is IPageViewModel);
                

                return changePageCommand;
            
        


        public List<IPageViewModel> PageViewModels
        
            get
            
                if (_pageViewModels == null)
                    _pageViewModels = new List<IPageViewModel>();
                return _pageViewModels;
            
        

        public IPageViewModel CurrentPageViewModel
        
            get
            
                return _currentPageViewModel;
            
            set
            
                if (_currentPageViewModel != value)
                
                    _currentPageViewModel = value;
                    OnPropertyChanged("CurrentPageViewModel");
                
            
        

        #endregion

        #region Methods

        private void ChangeViewModel(IPageViewModel viewModel)
        
            if (!PageViewModels.Contains(viewModel))
                PageViewModels.Add(viewModel);
            CurrentPageViewModel = PageViewModels.FirstOrDefault(vm => vm == viewModel);
        

        #endregion
    

在public partial class App : Application protected override void OnStartup(StartupEventArgs e) base.OnStartup(e); MainWindow app = new MainWindow(); ApplicationViewModel context = new ApplicationViewModel(); app.DataContext = context; app.Show(); 里面我有简单的<Window.Resources> <DataTemplate DataType="x:Type home:HomeViewModel"> <home:HomeView /> </DataTemplate> <DataTemplate DataType="x:Type options:OptionsViewModel"> <options:OptionsView /> </DataTemplate> </Window.Resources> ：

HomeView.xaml

我想添加简单的button命令，一些东西。

所以我尝试添加这个<Button Command="Binding DataContext.AddFilesCommand, RelativeSource=RelativeSource AncestorType=x:Type Window" CommandParameter="Binding"/> ：

Click

有关如何在每个ICommand之后执行的命令上添加此类的任何建议吗？

答案

这可以轻松完成。我会创建一个类来轻松实现命令：

public ICommand AddFilesCommand

然后创建命令（您不需要私有ICommand）：

Button Click

并像这样使用它（在构造函数中）：

using System;
using System.Windows.Input;

namespace YourNameSpace

    public class RelayCommand : ICommand
    
        private Action Action;

        public Command(Action _action)
        
            Action = _action;
        

        public event EventHandler CanExecuteChanged = (sender, e) =>  ;

        public bool CanExecute(object parameter) => true;

        public void Execute(object parameter)
        
            Action();
        
    

XAML：

public ICommand AddFileCommand  get; set; 

这样您的代码将更容易透视。