即使在ItemsSource中缺少绑定值，Combobox也应显示绑定值 [英] Combobox should display bound value even if it's missing in ItemsSource

问题描述

在WinForms组合框的情况下，即使其数据源中不存在绑定值，组合框仍将显示值（不是描述）。

In case of WinForms combobox, even if the bound value was not present in its datasource, the combobox would still show the value (not the description).

但是，在类似的情况下，Wpf组合框是空白的。为什么WPF中缺少此功能？我检查了组合框的代码 - 如果ItemsSource集合中不存在该项，则它不会设置SelectedValue。

However, the Wpf combobox is blank in a similar case. Why is this feature missing in WPF? I checked the code for combobox - it doesn't set the SelectedValue if the item doesn't exist in the ItemsSource collection.

总结：如果绑定值（例如：6）不是在数据源中找到，

To summarize: If bound value (eg: 6) is not found in datasource,

WinForms组合框：

WinForms combobox:

• SelectedItem = null
• SelectedValue = 6
• Text =" 6"

WPF组合框：

• SelectedItem = null
• SelectedValue = null
• Text = null

在这种特殊情况下，如何让WPF组合框像winforms组合框一样工作？

How can I make WPF combobox work like winforms combobox in this particular case?

推荐答案

以下XAML

<ComboBox
   IsEditable="True"
   ItemsSource="{Binding Path=Texts}"
   SelectedItem="{Binding Path=SelectedTextI}"
   SelectedValue="{Binding Path=SelectedTextV}"
   Text="{Binding Path=Text}" />

结合DataContext，如

combined with a DataContext like

 public class ViewModel
 {
    public ViewModel()
    {
       this.Texts = new List<string> { "one","two","three" };
    }

    public string SelectedTextI { get; set; }
    public string SelectedTextV { get; set; }
    public string Text { get; set; }
    public List<string> Texts { get; set; }
 }

产生ViewModel.Text，无论你在ComboBox中输入什么内容。

yields to ViewModel.Text whatever you type in the ComboBox.

干杯
$ b $bJürgen

Cheers
Jürgen

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