c# - 如果存在验证错误，也要更新 ViewModel 中的属性

Question

在我的应用程序中，我对 DataGridTemplateColumn 有以下定义:

<DataGridTemplateColumn Header="Placeholder-Name" Width="*">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <ComboBox IsEditable="True" VerticalAlignment="Center" Margin="2"
                      ItemsSource="{Binding DataContext.AvailablePlaceholders, RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}"
                      DisplayMemberPath="PlaceholderName"
                      Validation.ErrorTemplate="{StaticResource ComboBoxErrorTemplate}">
                <ComboBox.Text>
                    <Binding Path="PlaceholderName" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
                        <Binding.ValidationRules>
                            <local:PlaceholderValidationRule>
                                <local:PlaceholderValidationRule.PlaceholderValidationRuleParamData>
                                    <local:PlaceholderValidationRuleParamData 
                                        UsedPlaceholders="{Binding Source={StaticResource proxy}, Path=Data.PlaceholderItems}"
                                        AvailablePlaceholders="{Binding Source={StaticResource proxy}, Path=Data.AvailablePlaceholders}"/>
                                </local:PlaceholderValidationRule.PlaceholderValidationRuleParamData>
                            </local:PlaceholderValidationRule>
                        </Binding.ValidationRules>
                    </Binding>
                </ComboBox.Text>
            </ComboBox>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

一切正常，但我刚刚意识到，如果 PlaceholderValidationRule 报告无效的结果，我的 ViewModel 中的属性 PlaceholderName 是 ComboBox - 文本必然不会被更新。

如果存在验证错误，是否有任何方法可以从 View 更新 ViewModel 中的属性？

Answer 1

Is there any way to update the property in the ViewModel from the View also if there are Validation-Errors?

设置ValidationStep ValidationRule 的属性(property)至UpdatedValue :

<local:PlaceholderValidationRule ValidationStep="UpdatedValue">

这将导致验证规则在源属性更新后运行。