INotifyPropertyChanged：通知另一个类

问题描述

我有一个类（让我们称之为 c>中更改 Count / code>到 ClassF 。但是我的datagrid中的最后一列保持不变。任何线索？

Then I have a datagrid, and each row has one object of MyContainerClass. The columns of the grid show ClassA to ClassF. The last column in the grid shows a total (that is it is bound the Count property of MyContainerClass). Now I want that the total in the last column updates as soon as I change the Count property in any class in the A-F range. I implemented INotifyPropertyChanged in MyBaseClass and it does fire when I change the Count property in ClassA to ClassF. But the last column in my datagrid remains the same. Any clues?

编辑：
我创建了一个类图。

I have created a class diagram.

getCount（）方法返回objA.Count + objB.Count + ... + objF.Count，并由 MyContainerClass 属性返回>。问题是：如果我更新objA.Count我想要GUI（即我的datagrid中的列）显示更新的和。

The getCount() method returns objA.Count+objB.Count+...+objF.Count and is returned by the Count property in the MyContainerClass. The question is: if I update objA.Count I want the GUI (that is the column in my datagrid) to display the updated sum.

推荐答案

只需实现 INotifyPropertyChanged 不足以进行自动更新。 MyContainerClass 对象需要订阅其他列中的 MyBaseClass 对象的更改通知。您可以通过将以下方法添加到 MyContainerClass 中：

Just implementing INotifyPropertyChanged is not enough for an automatic update. The MyContainerClass object needs to "subscribe" to the change notifications of the MyBaseClass objects in the other columns. One way you can handle this is by adding a method like the following to the MyContainerClass:

void SubscribeToCount(MyBaseClass item)
{
    item.PropertyChanged += (s,e) =>
        this.Sum += (e.NewValue - e.OldValue);
}

您可以为其他列中的所有对象调用此方法。 （这个问题不清楚，但是我假设有一个包装类，其中包含 MyClassA-F 和 MyContainerClass ，它将数据网格绑定到这个包装器类的集合）。

And you call this method for all the objects in the other columns. (It's not clear from the question but I assume there is a wrapper class that includes instances of MyClassA-F and MyContainerClass, which you bind the datagrid to a collection of this wrapper class).

这篇关于INotifyPropertyChanged：通知另一个类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！