更新ViewModel属性时如何避免递归？

Question

在我的视图中,我有一个滑块和一个组合框.

当我更改滑块时,我希望组合框改变.

当我更改组合框时,我想要更改滑块.

我可以使用其中一个,但如果我尝试更新两个,我会收到StackOverflow错误,因为一个属性在无限循环中不断更新另一个属性.

我已经尝试进入一个Recalculate(),其中更新在一个地方完成,但仍然遇到递归问题.

如何在不进行递归的情况下让每个控件更新另一个？

在视图中:

<ComboBox 
    ItemsSource="{Binding Customers}"
    ItemTemplate="{StaticResource CustomerComboBoxTemplate}"
    Margin="20"
    HorizontalAlignment="Left"
    SelectedItem="{Binding SelectedCustomer, Mode=TwoWay}"/>


<Slider Minimum="0" 
        Maximum="{Binding HighestCustomerIndex, Mode=TwoWay}" 
        Value="{Binding SelectedCustomerIndex, Mode=TwoWay}"/>

在ViewModel中:

#region ViewModelProperty: SelectedCustomer
private Customer _selectedCustomer;
public Customer SelectedCustomer
{
    get
    {
        return _selectedCustomer;
    }

    set
    {
        _selectedCustomer = value;
        OnPropertyChanged("SelectedCustomer");
        SelectedCustomerIndex = _customers.IndexOf(_selectedCustomer);
    }
}
#endregion

#region ViewModelProperty: SelectedCustomerIndex
private int _selectedCustomerIndex;
public int SelectedCustomerIndex
{
    get
    {
        return _selectedCustomerIndex;
    }

    set
    {
        _selectedCustomerIndex = value;
        OnPropertyChanged("SelectedCustomerIndex");
        SelectedCustomer = _customers[_selectedCustomerIndex];
    }
}
#endregion

Answer 1

尝试设置函数类似于:

public int SelectedCustomerIndex
{
    get
    {
        return _selectedCustomerIndex;
    }

    set
    {
        if (value != _selectedCustomerIndex)
        {
         _selectedCustomerIndex = value;
         OnPropertyChanged("SelectedCustomerIndex");
         SelectedCustomer = _customers[_selectedCustomerIndex];
        }
    }
}

仅在值发生实际变化时触发事件.这样,第二次调用具有相同值的set属性不会导致另一个更改事件.

当然,你必须为其他财产这样做.