MVVM学习(一)

最新推荐文章于 2025-08-09 22:19:42 发布

weixin_30835923

最新推荐文章于 2025-08-09 22:19:42 发布

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CC 4.0 BY-SA版权

文章标签： c#

原文链接：http://www.cnblogs.com/lecon/archive/2013/02/24/2923937.html

View的C#代码

View Code

using System.Windows;

namespace WpfApplication4
{
    /// <summary>
    /// Interaction logic for RegisterUserView.xaml
    /// </summary>
    public partial class RegisterUserView : Window
    {
        public RegisterUserView()
        {
            InitializeComponent();

            this.ViewModel = new RegisterUserViewModel();
            this.ViewModel.View = this;
            this.ViewModel.PropertyChanged += new System.ComponentModel.PropertyChangedEventHandler(ViewModel_PropertyChanged);
        }

        void ViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            // this.tbAge.Text = this.ViewModel.Age.ToString();
            ;
        }

        public RegisterUserViewModel ViewModel
        {
            get 
            {
                return this.DataContext as RegisterUserViewModel;
            }
            set 
            {
                this.DataContext = value;
            }
        }
    }
}

View的XAML代码

 <Grid>
        <Button Height="23" HorizontalAlignment="Left" Margin="12,0,0,72" Name="btnClick" VerticalAlignment="Bottom" Width="75" Command="{Binding ClickCommand}">Click me</Button>
        <TextBlock Height="21" Margin="12,44,0,0" Name="textBlock1" VerticalAlignment="Top" Text="UserName:" HorizontalAlignment="Left" Width="62" />
        <TextBlock Margin="12,93,0,0" Name="textBlock2" Height="21" HorizontalAlignment="Left" VerticalAlignment="Top" Width="62" Text="Age:" />
        <TextBlock Height="21" Margin="99,44,117,0" Name="tbUserName" Text="{Binding Path=UserName, Mode=OneTime}" VerticalAlignment="Top" />
        <TextBlock Height="21" Margin="99,93,117,0" Name="tbAge" Text="{Binding Age}" VerticalAlignment="Top" />
    </Grid>

这两行是在View里面把ViewModel绑定到Windows.DataContext,这样在XAML里才可以藉由后期用Text="{Binding Age}"绑定,

命今是通过Command="{Binding ClickCommand}"绑定,Age和ClickCommand是在RegisterUserViewModel中实现的

this.ViewModel = new RegisterUserViewModel();
this.ViewModel.View = this;

下面把RegisterUserViewModel的代码贴出来,RegisterUserViewModel实现了INotifyPropertyChanged,所以可以在View中编写响应这个事件的委托,以便及时刷新View,但在此例中不在View中编写委托也可以,因为ViewModule已经绑定到tbAge的Text属性上了,注意到Age是int类型,Text是string类型,自动做了类型转换的工作.

namespace WpfApplication4
{
    public class RegisterUserViewModel : INotifyPropertyChanged
    {
        public RegisterUserViewModel()
        {
            this.UserName = "Baobao";
            this.Age = 27;

            ClickCommand = new DelegateCommand<object>(OnClick, arg => true);
        }

        void OnClick(object obj)
        {
            this.Age += 1;
        }

        public RegisterUserView View { get; set; }

        public ICommand ClickCommand { get; set; }

        public string UserName { get; set; }

        private int age;
        public int Age
        {
            get 
            { 
                return this.age; 
            }
            set
            {
                if (this.age != value)
                {
                    this.age = value;
                    //如果直接引用View则耦合了
                    //if(View!=null) View.tbAge.Text = value.ToString() ;
                     OnPropertyChanged("Age");
                }
            }
        }
        
        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        #endregion
    }
}