单个绑定有多个验证规则

Question

可以在单个绑定上使用多个验证规则吗？我正在尝试TextBox仅使用XAML 进行验证，BindingGroup但似乎无法正常工作。

这是我的XAML：

<TextBox>
    <TextBox.Text>
        <Binding Path="Title" UpdateSourceTrigger="PropertyChanged"/>
    </TextBox.Text>
    <TextBox.BindingGroup>
        <BindingGroup NotifyOnValidationError="True">
            <BindingGroup.ValidationRules>
                <rule:CantBeEmpty ValidatesOnTargetUpdated="True" />
                <rule:CantBeMoreThanXCharacters
                    CharacterLimit="30"
                    ValidatesOnTargetUpdated="True" />
            <BindingGroup.ValidationRules/>
        </BindingGroup>
    </TextBox.BindingGroup>
</TextBox>

凡rule命名空间引用xmlns:rule="clr-namespace:MyApp.Views.ValidationRules" 这些规则遵循标准的语法：

public class CantBeEmpty : ValidationRule {
    public override ValidationResult Validate(object value, CultureInfo cultureInfo) {
        [...]
    }
}

Answer 1

您是否尝试将验证规则添加到绑定中？：

<TextBox>
    <TextBox.Text>
        <Binding Path="Title" UpdateSourceTrigger="PropertyChanged">
            <Binding.ValidationRules>
                <rule:CantBeEmpty ValidatesOnTargetUpdated="True" />
                <rule:CantBeMoreThanXCharacters CharacterLimit="30" ValidatesOnTargetUpdated="True" />
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
</TextBox>