调用 RaiseCanExecuteChanged 后 ListView 未更新
我有一个绑定到视图模型集合的 ListView。项目模板包含一个绑定到视图模型上的命令的按钮。当我设置 ListView 的 ItemsSource 的属性时，我为每个视图模型调用 RaiseCanExecuteChanged 。
public BindingList<IVehicleViewModel> Vehicles
{
get { return _vehicles; }
set
{
if(_vehicles == value) return;
_vehicles = value;
OnPropertyChanged("Vehicles");
RaiseCanExecuteChangedEvents();
}
}
尽管我已经验证所有视图模型上的 CanExecute 返回 true，但该按钮显示为灰色。 我注意到的唯一一件事是，如果我在列表视图已经呈现时调用 RaiseCanExecuteChanged ，那么一切都会按预期工作，并且如果我在列表视图呈现之前调用它，然后滚动浏览它们自行排序的项目。
I have a ListView that is bound to a collection of view models. The Item template contains a button that is bound to a command on the view model. When I set the property that the ItemsSource of the ListView I call RaiseCanExecuteChanged for each viewmodel.
public BindingList<IVehicleViewModel> Vehicles
{
get { return _vehicles; }
set
{
if(_vehicles == value) return;
_vehicles = value;
OnPropertyChanged("Vehicles");
RaiseCanExecuteChangedEvents();
}
}
Despite the fact that I have verified that true is returned for the CanExecute on all view models the button shows as greyed out.
The only thing I have noticed is that if I call RaiseCanExecuteChanged when the listview has already been rendered everything works as expected and if I call it before the listview has been rendered and then scroll through the items they sort themselves out.
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有一个静态方法 CommandManager.InvalidateRequerySuggested 会强制重新评估命令的可执行性（这是一个词吗？），每当您想要确保 UI 更新以反映 CanExecute 中的更改时，请尝试调用该方法 你的命令的结果。
There's a static method
CommandManager.InvalidateRequerySuggestedwhich forces a reevaluation of command executability (is that a word?) try calling that whenever you want to make sure your UI updates to reflect a change in theCanExecuteresult of your command.