Question

我对C＃中的财产变更处理存有疑问。我的场景如下：我有两个班级

public class CustomerSupplier : ViewModelBase
{
    public Customer Customer { get; set; }

    private IEnumerable<SupplierSelect> suppliersSelect;
    public IEnumerable<SupplierSelect> SuppliersSelect 
    {
        get
        {
            return suppliersSelect;
        }
        set
        {
            suppliersSelect = value;
            this.NotifyPropertyChanged("SuppliersSelect");
        }
    }
}

public class SupplierSelect : ViewModelBase
{
    public Supplier Supplier { get; set; }

    private bool selected;
    public bool Selected 
    {
        get
        {
            return selected;
        }
        set
        {
            selected = value;
            this.NotifyPropertyChanged("Selected");
        }
    }
}

ViewModelBase以通常的方式实现NotifyPropertyChanged。在我的CustomersViewModel中，我有一个CustomerSupplier类型的属性来处理关系。我需要的是从CustomersViewModel内部检测到SupplierSelect类的Selected属性的更改。我该怎么做？

提前感谢您的帮助。

Answer 1

这样的事情：

public class CustomerSupplier : ViewModelBase
{
    public Customer Customer { get; set; }

    private void HandleSupplierSelectPropertChanged(object sender, PropertyChangedEventArgs args)
    {
        if (args.PropertyName == "Selected")
        {
            var selectedSupplier = (SupplierSelect)sender;
            // ...
        }
    }

    private IEnumerable<SupplierSelect> suppliersSelect;
    public IEnumerable<SupplierSelect> SuppliersSelect 
    {
        get
        {
            return suppliersSelect;
        }
        set
        {
            if (suppliersSelect != value)
            {
               if (suppliersSelect != null)
               {
                   foreach (var item in suppliersSelect)
                       item.PropertyChanged -= HandleSupplierSelectPropertChanged;
               }

               suppliersSelect = value;

               if (suppliersSelect != null)
               {
                   foreach (var item in suppliersSelect)
                       item.PropertyChanged += HandleSupplierSelectPropertChanged;
               }

               this.NotifyPropertyChanged("SuppliersSelect");
            }
        }
    }
}

另请注意：如果IEnumerable<SupplierSelect>的实际类型实现了INotifyCollectionChanged，那么您必须监视集合更改，以分别为新/旧项目订阅/取消订阅PropertyChanged事件。

Answer 2

当您分配新的SupplierSelect时，会在CustomerSupplier中为SupplierSelect的PropertyChanged事件添加处理程序。

处理财产变更事件

2 个答案: