数据改变后更新UI（SetProperty/RaiseCanExecuteChanged）

View代码

 <StackPanel>
            <TextBlock Text="方法一"></TextBlock>
            <TextBox Text="{Binding Value1}"></TextBox>
            <TextBlock Text="方法二"></TextBlock>
            <TextBox Text="{Binding Value2}"></TextBox>
            <TextBlock Text="方法三"></TextBlock>
            <TextBox Text="{Binding Value3}"></TextBox>
            <TextBlock Text="方法四"></TextBlock>
            <TextBox Text="{Binding Value4}"></TextBox>
            <TextBlock Text="方法五"></TextBlock>
            <TextBox Text="{Binding Value5}"></TextBox>
            <Button Content="方法一" Command="{Binding AddCommand1}"></Button>
            <Button Content="方法二" Command="{Binding AddCommand2}"></Button>
            <Button Content="方法三" Command="{Binding AddCommand3}"></Button>
            <Button Content="方法四" Command="{Binding AddCommand4}"></Button>
            <Button Content="方法五" Command="{Binding AddCommand5}"></Button>
        </StackPanel>

ViewModel代码

 public class MainWindowViewModel : BindableBase
    {
        private string _title = "Prism命令学习";
        public string Title
        {
            get
            {
                return _title;
            }
            set
            {
                SetProperty(ref _title, value);
            }
        }

       
        public MainWindowViewModel()
        {
            //方法一
            AddCommand1 = new DelegateCommand(Add1);
           
            //方法二
            AddCommand2 = new DelegateCommand(Add2);
            //方法三
            AddCommand3 = new DelegateCommand(Add3);
            //方法四
            AddCommand4 = new DelegateCommand(Add4);
            //方法五：布尔类型,可以使控件不能使用变灰
            AddCommand5 = new DelegateCommand(Add5).ObservesCanExecute(() => Value5);

        }
        private Random random = new Random();
        //方法一
        private string _value1 = "Prism命令学习";
        public string Value1
        {
            get
            {
                return _value1;
            }
            set
            {
                SetProperty(ref _value1, value);
            }
        }
        public DelegateCommand? AddCommand1
        {
            set; get;
        }       
        private void Add1()
        {
            //写入需要执行的代码；

            Value1 =random.Next().ToString();
            MessageBox.Show(Value1);
        }



        //方法二
        private string _value2 = "Prism命令学习";
        public string Value2
        {
            get
            {
                return _value2;
            }
            set
            {
                SetProperty(ref _value2, value);
                AddCommand2.RaiseCanExecuteChanged();
            }
        }
        public DelegateCommand? AddCommand2
        {
            set; get;
        }

      
        private void Add2()
        {
            //写入需要执行的代码；

            Value2= random.Next().ToString();
            MessageBox.Show(Value2);
        }


        //方法三
        private string _value3 = "Prism命令学习";
        public string Value3
        {
            get
            {
                return _value3;
            }
            set
            {
                _value3 = value;
                RaisePropertyChanged(nameof(Value3));
                //也可以这样
                RaisePropertyChanged();

            }
        }
        public DelegateCommand? AddCommand3
        {
            set; get;
        }


        private void Add3()
        {
            //写入需要执行的代码；

            Value3 = random.Next().ToString();
            MessageBox.Show(Value3);
        }
        //方法四
        private string _value4 = "Prism命令学习";
        public string Value4
        {
            get
            {
                return _value4;
            }
            set
            {
                _value4 = value;
              OnPropertyChanged(new System.ComponentModel.PropertyChangedEventArgs(nameof(Value4)));

            }
        }
        public DelegateCommand? AddCommand4
        {
            set; get;
        }


        private void Add4()
        {
            //写入需要执行的代码；

            Value4 = random.Next().ToString();
            MessageBox.Show(Value4);
        }
        //方法五
        private bool _value5= false;
        public bool Value5
        {
            get
            {
                return _value5;
            }
            set
            {
                _value5 = value;
                SetProperty(ref _value5, value);
              

            }
        }
        public DelegateCommand? AddCommand5
        {
            set; get;
        }


        private void Add5()
        {
            //写入需要执行的代码；

            Value5=true;
            MessageBox.Show(Value5.ToString());
        }
    }