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MVVM事件-在MVVM体系结构中,它们应该如何发生以及在何处发生?

wpf-controls wpf

yoav.str · 技术社区 · 14 年前

假设我有一个主窗口xmal:

<Window x:Class="MVVMTUTRIALS.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:views="clr-namespace:TestMvvm444.Views"
Title="Window1" Height="300" Width="400" Loaded="Window_Loaded">
<Grid>
    <views:CustomersList x:Name="CustomersList"/>
    <views:CustomerBoughtList x:Name="CustomerBoughtList"/>
</Grid>
</Window>

我想要一个在CustomersList(点击cerrtian raw)中调用规则的事件

1.活动应该在哪里?在主窗口思考是合理的吗?

有人能指导我怎么做吗?

我认为我误解的核心是两个UserControl(s)如何相互通信以及如何与视图模型通信

谢谢你阅读和做笔记。

2 回复 | 直到 14 年前

Tim Cooper 13 年前

有多种方法可以解决这个问题。下面是用伪代码表示的一对。首先,协调视图模型:

public class CustomersViewModel : ViewModel
{
    public event EventHandler<EventArgs> SelectedCustomerChanged;

    public ICollection<Customer> Customers
    {
        get ...
    }

    public CustomerViewModel SelectedCustomer
    {
        get ...
        set ...
    }
}

public class CustomerPurchasesViewModel : ViewModel
{
    public CustomerViewModel Customer
    {
        get ...
        set ...
    }

    public ICollection<PurchaseViewModel> Purchases
    {
        get ...
    }
}

public class MainViewModel : ViewModel
{
    private CustomersViewModel customers;
    private CustomerPurchasesViewModel customerPurchases;

    public MainViewModel(CustomersViewModel customers, CustomerPurchasesViewModel customerPurchases)
    {
        this.customers = customers;
        this.customerPurchases = customerPurchases;

        // push changes in selection to the customer purchases VM
        this.customers.SelectedCustomerChanged += delegate
        {
            this.customerPurchases.Customer = this.customers.SelectedCustomer;
        };
    }
}

public class CustomersViewModel : ViewModel
{
    public ICollection<Customer> Customers
    {
        get ...
    }

    public CustomerViewModel SelectedCustomer
    {
        get ...
        set
        {
            ...
            eventHub.Publish(new CustomerSelectedMessage(value));
        }
    }
}

public class CustomerPurchasesViewModel : ViewModel, ISubscriber<CustomerSelectedMessage>
{
    public CustomerViewModel Customer
    {
        get ...
        set ...
    }

    public ICollection<PurchaseViewModel> Purchases
    {
        get ...
    }

    private void Receive(CustomerSelectedMessage m)
    {
        this.Customer = e.Customer;
    }
}

public class MainViewModel : ViewModel
{
    private CustomersViewModel customers;
    private CustomerPurchasesViewModel customerPurchases;

    public MainViewModel(CustomersViewModel customers, CustomerPurchasesViewModel customerPurchases)
    {
        this.customers = customers;
        this.customerPurchases = customerPurchases;
    }
}

-1

Mark Bostleman 14 年前

主窗口的视图模型可以有两个公共列表属性,用户控件可以绑定到这两个属性。然后,在视图中更改选择时,可以在视图模型列表中检测到该选择,并对其他列表执行任何需要执行的操作。视图中没有事件处理。