简单的 WPF 组合框过滤器
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Simple WPF combobox filter
提问by BabyDoll
I have searched Google for a simple solution to this but no luck. I have a standard WPF combo box which I would simply like to be able to filter the list displayed according to the first 2 or 3 letters a users types when the combo box has focus. I tried some coding including some lamba expressions but the error "System.NotSupportedException" keeps getting thrown on the line where "combobox.Items.Filter" is specified. I'm not using MVVM and would just like this simple functionality available for the user. Please help! P.S. IsEditable, IsTextSearchEnabled and StaysOpenOnEdit properties are set to true but the desired functionality is not yet achieved.
我已经在谷歌上搜索了一个简单的解决方案，但没有运气。我有一个标准的 WPF 组合框，我只是希望能够在组合框具有焦点时根据用户键入的前 2 或 3 个字母过滤显示的列表。我尝试了一些编码，包括一些 Lamba 表达式，但是在指定“combobox.Items.Filter”的行上不断抛出错误“System.NotSupportedException”。我没有使用 MVVM，只是希望用户可以使用这个简单的功能。请帮忙！PS IsEditable、IsTextSearchEnabled 和 StaysOpenOnEdit 属性设置为 true，但尚未实现所需的功能。
回答by AnjumSKhan
I have developed a sample application. I have used string as record item, you can do it using your own entity. Backspace also works properly.
我开发了一个示例应用程序。我使用字符串作为记录项，您可以使用自己的实体来完成。Backspace 也可以正常工作。
public class FilterViewModel
{
public IEnumerable<string> DataSource { get; set; }
public FilterViewModel()
{
DataSource = new[] { "india", "usa", "uk", "indonesia" };
}
}
public partial class WinFilter : Window
{
public WinFilter()
{
InitializeComponent();
FilterViewModel vm = new FilterViewModel();
this.DataContext = vm;
}
private void Cmb_KeyUp(object sender, KeyEventArgs e)
{
CollectionView itemsViewOriginal = (CollectionView)CollectionViewSource.GetDefaultView(Cmb.ItemsSource);
itemsViewOriginal.Filter = ((o) =>
{
if (String.IsNullOrEmpty(Cmb.Text)) return true;
else
{
if (((string)o).Contains(Cmb.Text)) return true;
else return false;
}
});
itemsViewOriginal.Refresh();
// if datasource is a DataView, then apply RowFilter as below and replace above logic with below one
/*
DataView view = (DataView) Cmb.ItemsSource;
view.RowFilter = ("Name like '*" + Cmb.Text + "*'");
*/
}
}
XAML
XAML
<ComboBox x:Name="Cmb"
IsTextSearchEnabled="False"
IsEditable="True"
ItemsSource="{Binding DataSource}"
Width="120"
IsDropDownOpen="True"
StaysOpenOnEdit="True"
KeyUp="Cmb_KeyUp" />
回答by Ian
I think the CollectionView is what you are looking for.
我认为 CollectionView 就是你要找的。
public ObservableCollection<NdfClassViewModel> Classes
{
get { return _classes; }
}
public ICollectionView ClassesCollectionView
{
get
{
if (_classesCollectionView == null)
{
BuildClassesCollectionView();
}
return _classesCollectionView;
}
}
private void BuildClassesCollectionView()
{
_classesCollectionView = CollectionViewSource.GetDefaultView(Classes);
_classesCollectionView.Filter = FilterClasses;
OnPropertyChanged(() => ClassesCollectionView);
}
public bool FilterClasses(object o)
{
var clas = o as NdfClassViewModel;
// return true if object should be in list with applied filter, return flase if not
}
You wanna use the "ClassesCollectionView" as your ItemsSource for your Combobox
您想使用“ClassesCollectionView”作为组合框的 ItemsSource
