WPF组合框选择后丢失文本 [英] WPF Combobox loses Text after Selection

问题描述

我想要一个可搜索的组合框。当我在其中输入内容时，项目列表将被过滤。 OnTextChanged可以做到这一点。第二部分是，在组合框列表中，所有项目均以其简短描述显示，但是当我选择一个项目时，我希望显示键。在SelectionChanged上应该这样做，但是每次我选择一个项目时，组合框输入字段都会被覆盖。

I would like to have a searchable combobox. When I type something into it, the itemlist gets filtered. OnTextChanged does this quite fine. The second part is, inside the comboboxlist all the items are displayed with their shortdescription, but when I select an item, I want the key to be displayed. On SelectionChanged should do that, but everytime I select an item, the combobox input field gets overwritten with "".

private void OnTextChanged(object sender, TextChangedEventArgs e)
{
    ItemSource = new ObservableCollection<RoleKeyElementVM>(DataSource.Where(x => x.ShortDescription.Contains(RoleKeyCombobox.Text) || x.Key.ToString() == RoleKeyCombobox.Text));
    RoleKeyCombobox.ItemsSource = ItemSource;
}


private void OnSelectionChanged(object sender, EventArgs e)
{
    RoleKeyElementVM SelectedItem = RoleKeyCombobox.SelectedItem as RoleKeyElementVM;
    if(SelectedItem != null)
         RoleKeyCombobox.Text = SelectedItem.Key.ToString();
}

选择应如下所示：

The selection should look like this:

以及类似的过滤器

如何防止组合框用覆盖我的自定义文本？

How can I prevent the combobox from overwriting my custom text with a ""?

更新：

我们正在讨论的组合框：

The combobox we are talking about:

    <ComboBox 
        Name="RoleKeyCombobox"
        Margin="5" Grid.Column="2" Grid.Row="0"
        IsEditable="True"
        IsSynchronizedWithCurrentItem="False"
        TextBoxBase.TextChanged="OnTextChanged"
        SelectionChanged="OnSelectionChanged">
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding ShortDescription}"/>
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>

推荐答案

删除OnSelectionChanged

remove OnSelectionChanged

将以下内容添加到RoleKeyElementVM

add the following to the RoleKeyElementVM

public override string ToString()
{
    return this.Key;
}

更好吗？

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