wpf - ValidationRule WPF 的附加或依赖属性

Question

我想为 xaml 中的 ValidationRule 绑定 xaml 中的附加属性或依赖属性，然后根据附加属性或依赖属性的值，我想在验证规则中做出总和决定。我找不到任何解决方案如何将可绑定值传递给验证规则。

Answer 1

我为您提供了一个示例代码来帮助您。我已经定义了一个 ValidationRule 来验证 texbox 用户输入。验证的类型是根据一个枚举参数的值来执行的。可用的验证类型有：用户输入不能为空，用户输入必须是数字，用户输入必须是 IP 地址。第二个参数允许指定显示的警告消息。如您所知，用于绑定目的的变量应该是 DependendyProperty，所​​以在这里您可以找到带有参数声明的类。

    public class ValidationParams : DependencyObject
{
    // Dependency Properties
    public static readonly DependencyProperty MessageProperty = DependencyProperty.Register("Message",
                                                                                          typeof(string),
                                                                                          typeof(ValidationParams),
                                                                                          new FrameworkPropertyMetadata(string.Empty));

    public static readonly DependencyProperty ValidationTypeProperty = DependencyProperty.Register("ValidationType",
                                                                                          typeof(FieldValidationRule.EnmValidationType),
                                                                                          typeof(ValidationParams),
                                                                                          new FrameworkPropertyMetadata(FieldValidationRule.EnmValidationType.FieldNotEmpty));

    // Properties
    [Category("Message")]
    public string Message
    {
        get { return (string)GetValue(MessageProperty); }
        set { SetValue(MessageProperty, value); }
    }

    [Category("ValidationType")]
    public FieldValidationRule.EnmValidationType ValidationType
    {
        get { return (FieldValidationRule.EnmValidationType)GetValue(ValidationTypeProperty); }
        set { SetValue(ValidationTypeProperty, value); }
    }

然后是验证规则类：

    public class FieldValidationRule : ValidationRule
{
    public enum EnmValidationType
    {
        FieldNotEmpty,
        FieldNumeric,
        FieldIPAddress
    }

    // Local variables and objects
    private ValidationParams mParams = new ValidationParams();

    public ValidationParams Params
    {
        get { return mParams; }
        set { mParams = value; }
    }

    // Override
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        ValidationResult objResult = null;
        string sValue = value as string;
        objResult = new ValidationResult(true, null);
        switch (Params.ValidationType)
        {
            case EnmValidationType.FieldNotEmpty:
                if(string.IsNullOrEmpty(sValue) == true)
                    objResult = new ValidationResult(false, Params.Message);
                break;
            case EnmValidationType.FieldNumeric:
                int iValue = 0;
                if(int.TryParse(sValue, out iValue) == false)
                    objResult = new ValidationResult(false, Params.Message);
                break;
            case EnmValidationType.FieldIPAddress:
                IPAddress objValue = IPMatrix.CreateHostAddr();
                if(IPAddress.TryParse(sValue, out objValue) == false)
                    objResult = new ValidationResult(false, Params.Message);
                break;
        }
        return objResult;
    }
}

最后是 XAML 代码：

                        <TextBox Style="{DynamicResource FieldValue}" Grid.Column="1" IsReadOnly="False">
                        <TextBox.Text>
                            <Binding Source="{StaticResource XmlItemChannel}" XPath="@Name" Mode="TwoWay" UpdateSourceTrigger="LostFocus">
                                <Binding.ValidationRules>
                                    <data:FieldValidationRule>
                                        <data:FieldValidationRule.Params>
                                            <data:ValidationParams Message="{DynamicResource ERR002}" ValidationType="FieldNotEmpty" />
                                        </data:FieldValidationRule.Params>
                                    </data:FieldValidationRule>
                                </Binding.ValidationRules>
                            </Binding>
                        </TextBox.Text>
                    </TextBox>

您可以看到参数 Message 已绑定到资源，但您也可以经典地绑定它。