Question

我正在使用文章Model View View-Model (MVVM) in Silverlight作为在Silverlight中创建自己的MVVM示例的基础。

我已经收到了以下所有内容：

主页（加载所有内容）
查看（带绑定的XAML文件）
模型（生成虚假列表集合的Customer类）
ModelView （继承INotifyPropertyChanged并为View需要的两个字段设置PropertyChanged）

在我的主页I：

创建 ViewModel
将 ViewModel 绑定到查看

DataContext

创建模型（客户）

但是现在我如何将ModelView连接到Model？我觉得我需要将我的客户Model以某种方式注入CustomerViewModel，是吗？但到底怎么样？完成此MVVM示例的下一步是什么，以便我可以开始使用MVVM模式的优点，例如使用测试模型交换模型，使用新视图交换视图等。

MainPage.xaml.cs： 创建ViewModel，将View附加到ViewModel

using System.Windows.Controls;
using System.Collections.Generic;

namespace TestMvvm345
{
    public partial class MainPage : UserControl
    {
        private CustomerViewModel customerData;

        public MainPage()
        {
            InitializeComponent();

            customerData = new CustomerViewModel();
            customerHeaderView.DataContext = customerData;
            List<Customer> customers = Customer.GetCustomers();
        }
    }
}

MainPage.xaml： 在主页的上下文中显示视图

<UserControl x:Class="TestMvvm345.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:local="clr-namespace:TestMvvm345"
    Width="400" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel HorizontalAlignment="Left">
            <local:CustomerHeaderView x:Name="customerHeaderView" Margin="10"/>
        </StackPanel>
    </Grid>
</UserControl>

CustomerViewModel.xaml： ViewModel

using System.ComponentModel;

namespace TestMvvm345
{
    public class CustomerViewModel : INotifyPropertyChanged
    {
        private string firstName;
        private string lastName;

        public string FirstName
        {
            get { return firstName; }
            set
            {
                firstName = value;
                RaisePropertyChanged("FirstName");
            }
        }

        public string LastName
        {
            get { return lastName; }
            set
            {
                lastName = value;
                RaisePropertyChanged("LastName");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void RaisePropertyChanged(string property)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(property));
            }
        }
    }
}

CustomerHeaderView.xaml 视图

<UserControl x:Class="TestMvvm345.CustomerHeaderView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel HorizontalAlignment="Left">
            <ListBox x:Name="CustomerList" ItemsSource="{Binding}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock
                            Text="{FirstName}"/>
                            <TextBlock
                            Text="{LastName}"/>
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </StackPanel>
    </Grid>
</UserControl>

Customers.cs 模型

using System;
using System.Collections.Generic;

namespace TestMvvm345
{
    public class Customer
    {
        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int NumberOfContracts { get; set; }

        public static List<Customer> GetCustomers()
        {
            List<Customer> customers = new List<Customer>();
            customers = new List<Customer>();
            customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", NumberOfContracts = 23 });
            customers.Add(new Customer { FirstName = "Jane", LastName = "Smith", NumberOfContracts = 22 });
            customers.Add(new Customer { FirstName = "John", LastName = "Tester", NumberOfContracts = 33 });
            customers.Add(new Customer { FirstName = "Robert", LastName = "Smith", NumberOfContracts = 2 });
            customers.Add(new Customer { FirstName = "Hank", LastName = "Jobs", NumberOfContracts = 5 });
            return customers;
        }
    }
}

Answer 1

我使用ViewModel的方式有些不同。在我的例子中，它实际上包装了Model类，将大部分数据传递给模型。这样，模型中的所有标准业务规则仍然可以按照它们应该的方式运行。 ViewModel仅公开数据绑定或其他UI目的实际需要的属性。此外，ViewModel可能包含用于数据绑定的其他属性/方法。

所以使用您的客户示例：命名空间TestMvvm345 { 公共类CustomerViewModel：INotifyPropertyChanged {

    private Customer _model;
    public Customer Model
    {
        get
        { return _model; }
        set
        {
            if (_model != null)
                Model.PropertyChanged -= Model_PropertyChanged;

            _model = value;

            if (_model != null)
                Model.PropertyChanged += Model_PropertyChanged;
        }
    }

    void Model_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        RaisePropertyChanged(e.PropertyName);
        if (e.PropertyName == "FirstName" || e.PropertyName == "LastName")
            RaisePropertyChanged("FullName");
    }

    public string FirstName
    {
        get { return Model.FirstName; }
        set { Model.FirstName = value; }
    }

    public string LastName
    {
        get { return Model.LastName; }
        set { Model.LastName = value; }
    }

    public string FullName
    {
        get { return FirstName + " " + LastName; }
    }


    public static IList<CustomerViewModel> GetCustomers()
    {
        var result = new List<CustomerViewModel>();
        var customers = Customer.GetCustomers();
        foreach (var customer in customers)
        {
            result.Add(new CustomerViewModel() { Model = customer });
        }
        return result;
    }
    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged(string property)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}


public class Customer : INotifyPropertyChanged
{
    public int ID { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int NumberOfContracts { get; set; }

    public static List<Customer> GetCustomers()
    {
        List<Customer> customers = new List<Customer>();
        customers = new List<Customer>();
        customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", NumberOfContracts = 23 });
        customers.Add(new Customer { FirstName = "Jane", LastName = "Smith", NumberOfContracts = 22 });
        customers.Add(new Customer { FirstName = "John", LastName = "Tester", NumberOfContracts = 33 });
        customers.Add(new Customer { FirstName = "Robert", LastName = "Smith", NumberOfContracts = 2 });
        customers.Add(new Customer { FirstName = "Hank", LastName = "Jobs", NumberOfContracts = 5 });
        return customers;
    }

    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

    #endregion
}

}

现在在您的UI中使用以下代码进行绑定： customerHeaderView.DataContext = CustomerViewModel.GetCustomers（）;

ViewModel中的代码确实变得有点大，但可以将很多内容放在基类中，并且所有转到模型的属性都完全相同（想想T4模板）。

如何在此Silverlight MVVM示例中将ModelView连接到Model？

1 个答案: