ReactiveUI如何使用WhenAnyObservable正确 [英] ReactiveUI How to use WhenAnyObservable properly
问题描述
我试图使用WhenAnyObservable首次。
I am attempting to use WhenAnyObservable for the first time.
在ReactiveList计数== 0和tipText长度> 0,那么我想在认购,或相反局部值设置为true。
When a ReactiveList Count == 0 and a tipText length is > 0 then I want to set a local value to true in the subscribe, or the opposite.
this.ViewModel.WhenAnyObservable(
x => x.AutoCompleteItems.CountChanged,
x => x.ObservableForProperty(y => y.TipText),
(countChanged, tipText) => countChanged == 0 && tipText.Length > 0);
我无法得到这个工作。
I am having trouble getting this to work.
有没有招我应该做的,或者我应该用另一种WhenAny命令吗?
Is there any trick I should be doing, or should I be using one of the other WhenAny commands?
推荐答案
您已经有了正确的想法,但WhenAnyObservable不会返回项目,直到它有一个初步的项目为双方如果你使用> 1观测量。所以,你可能想:
You've got the right idea, but WhenAnyObservable doesn't return items until it has an initial item for both "sides" if you use >1 Observables. So you probably want:
this.ViewModel.WhenAnyObservable(
x => x.AutoCompleteItems.CountChanged.StartWith(0),
x => x.WhenAnyValue(y => y.TipText),
(countChanged, tipText) => countChanged == 0 && tipText.Length > 0);
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