![](/img/trans.png)
[英]Only the first item in a list is rendered when I try to output a collectionview inside a collectionview in Xamarin Forms
[英]Can I bind to the first item of a CollectionView?
我將一個ListBox
綁定到在ViewModel(從現在開始的VM)上定義的ICollectionView
上。 我具有所選項目的屬性( SelectedFoo
),該屬性設置為VM構造函數中的第一個屬性。
當有人在文本框中輸入文本時,我會根據該輸入過濾集合(到目前為止,很好)。
應用某些過濾后,如何將所選索引設置為集合中的第一項? 我無法從代碼綁定到ICollectionView
的第一個對象。
有任何想法嗎?
這是一些簡化的代碼,包括List
,我在XAML中綁定到的ICollectionView
以及用於過濾的代碼在FooFilterString
,隨着用戶在文本框中鍵入內容,該代碼將更新。
// This is the underlying list
public List<Foo> FooList
{
get { return _fooList; }
set
{
if (Equals(value, _fooList)) return;
_fooList = value;
RaisePropertyChanged();
}
}
private List<Foo> _fooList;
// This is what the list box binds to
public ICollectionView FooListView
{
get { return _fooListView; }
set
{
if (Equals(value, _fooListView)) return;
_fooListView = value;
RaisePropertyChanged();
}
}
private ICollectionView _fooListView ;
// This is bound to from the XAML, as user types, it will filter the list.
// I want to bind to the first item of the filtered list.
public string FooFilterString
{
get { return _fooFilterString; }
set
{
_fooFilterString = value;
FooListView.Filter = (s => some_logic); // <-- filters the list
/*
* How can I set the selected index here ?!
*/
}
}
private string _fooFilterString;
// I Bind to this, and want to set this after filtering. First time, I just
// set it to the first item from the FooList, but after filtering, I'm loosing
// the selection
public Foo SelectedFoo {
get { /*...*/ }
set { /*...*/ }
}
private Foo _selectedFoo;
要匯總注釋以從ICollectionView
選擇第一項,可以使用ICollectionView.MoveCurrentToFirst()
FooListView.Filter = s => some_logic;
FooListView.MoveCurrentToFirst()
您還需要啟用IsSynchronizedWithCurrentItem
<ListBox ... IsSynchronizedWithCurrentItem="True">
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.