WPF 可搜索组合框
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WPF searchable combobox
提问by LoPeZ
I've got a ComboBoxas follows:
我有一个ComboBox如下：
ComboBox IsEditable="True"
Width="200"
Height="25"
IsTextSearchEnabled="False"
x:Name="cb"
PreviewTextInput="Cb_OnPreviewTextInput"
ItemsSource="{Binding ItemList}"
Text="{Binding SearchTextText}">
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>
When Cb_OnPreviewTextInputis called I set IsDropdownOpen = true.
In the first attempt (after typing the first letter) the first item on the list is selected and I can go up and down using relevant arrows, the caret is still in the TextBox.
什么时候Cb_OnPreviewTextInput叫我设置IsDropdownOpen = true。在第一次尝试中（键入第一个字母后），选择了列表中的第一项，我可以使用相关箭头上下移动，插入符号仍在TextBox.
When I keep on typing at that point, I',m not able to navigate up and down (1 item at time) anymore, at this point the whole ScrollViewer gets focus and I can only go to the bottom or to the top, but not 1 by 1. I have to close the popup e.g. by pressing Escape and then reopen by typing 1 character to be able to go up/down again.
当我在那时继续打字时，我不能再上下导航（一次 1 个项目），此时整个 ScrollViewer 获得焦点，我只能转到底部或顶部，但是不是 1 个 1。我必须关闭弹出窗口，例如按 Escape，然后通过键入 1 个字符重新打开，以便能够再次向上/向下。
I also noticed that after pressing PageUp the first item gets selected as well, so I tried to mimic that in code, but no luck.
我还注意到按下 PageUp 后，第一个项目也被选中，所以我试图在代码中模仿它，但没有运气。
Anyone knows what to do here to be able to navigate up/down and type without problems?
任何人都知道在这里做什么才能毫无问题地向上/向下导航和输入？
回答by Zozo
When I have tried to reproduce your issue in isolated environment, everything seams to be fine...
当我试图在孤立的环境中重现您的问题时，一切都很好......
Which .NET version are you using?
您使用的是哪个 .NET 版本？
I have used code like this:
我使用过这样的代码：
<Window x:Class="InterviewApplication.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow"
Height="350"
Width="525"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<WrapPanel Orientation="Horizontal">
<ComboBox IsEditable="True"
Width="200"
Height="25"
IsTextSearchEnabled="False"
x:Name="cb"
PreviewTextInput="Cb_OnPreviewTextInput"
ItemsSource="{Binding ItemList}"
Text="{Binding SearchTextText}">
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>
</WrapPanel>
</Window>
and code behind looks like this
后面的代码看起来像这样
namespace Application
{
public partial class MainWindow : INotifyPropertyChanged
{
public MainWindow()
{
ItemList = new ObservableCollection<string>();
for (var i = 0; i < 1000; i++)
{
ItemList.Add($"Item {i}");
}
InitializeComponent();
}
private void Cb_OnPreviewTextInput(object sender, TextCompositionEventArgs e)
{
cb.IsDropDownOpen = true;
}
public ObservableCollection<string> ItemList { get; set; }
public string SearchTextText
{
get => _searchTextText;
set
{
if (_searchTextText == value) return;
_searchTextText = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SearchTextText)));
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
