c# - 单个绑定(bind)的多个验证规则

Question

能否在单个绑定(bind)上使用多个验证规则？ 我正在尝试仅使用 XAML 验证 TextBox，而 BindingGroup 似乎不起作用。

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>

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

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(bind)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>