wpf - RadCombobox 属性在 GotFocus 和 LostFocus 之间失去值(value)

Question

我有一个 radcombobox，其属性在 GotFocus 和 LostFocus 事件之间的某个位置失去了值。

XAML:

<telerik:RadComboBox x:Name="cboWoodSpecies" 
    FontSize="16"  Margin="0,4,0,0" Background="#F6F8FA" BorderBrush="#D7D8DD" 
    ItemsSource="{Binding}" Text="{Binding woodSpecies, Mode=TwoWay}" 
    telerik:TextSearch.TextPath="WoodSpecies" 
    IsEditable="True" IsReadOnly="True" TabIndex="0"
    Style="{DynamicResource RadComboBoxStyle3}" >

GotFocus 事件:

Private Sub cboWoodSpecies_GotFocus(sender As Object, e As RoutedEventArgs) Handles cboWoodSpecies.GotFocus

    BindComboBoxes.WoodSpecies(cboWoodSpecies)  'bind cbo to data


    If thisOrder.woodSpecies <> String.Empty Then   'Property OK here!!
        DisplayWoodSpeciesImage()
    End If
End Sub

DisplayWoodSpeciesImage 读取属性值，但不会将其重置为 Nothing。

失去焦点:

Private Sub cboWoodSpecies_LostFocus(sender As Object, e As RoutedEventArgs) Handles cboWoodSpecies.LostFocus

    If thisOrder.woodSpecies <> String.Empty Then   'Property = Nothing.  Why?!?!
        'do stuff
    End If

End Sub

我认为这与组合框本身有关。从组合中选择新项目不会导致问题。正是用现有数据填充组合才导致问题。我必须重新选择该项目才能绕过该错误。

话虽这么说，有没有办法刷新组合框，以便它认为该项目已被再次选择？是不是SelectedItem需要设置什么东西？

感谢您的帮助或建议。

Answer 1

尝试将ComboBox的SelectedValuePath设置为“WoodSpecies”并绑定(bind)SelectedValue(而不是Text属性)到“woodSpecies”:

<telerik:RadComboBox x:Name="cboWoodSpecies" 
FontSize="16"  Margin="0,4,0,0" Background="#F6F8FA" BorderBrush="#D7D8DD" 
ItemsSource="{Binding}"
SelectedValuePath="WoodSpecies"
SelectedValue="{Binding woodSpecies, Mode=TwoWay}" 
telerik:TextSearch.TextPath="WoodSpecies" 
IsEditable="True" IsReadOnly="True" TabIndex="0"
Style="{DynamicResource RadComboBoxStyle3}" >