1

我尝试为DataGridTextColumn应该测试 NHibernate 属性的可空性的 ValidationRule 实现。检查实际上是在我的HibernateConnector.isNullable(String className, String propertyName)方法内完成的。因此，必须将 HibernateConnector 传递给 ValidationRule。

下面引用的 mynamespace.TeamsForm.xaml.cs 有public HibernateConnector hibernateConnector { get; set; }

由于我对 WPF/XAML 很陌生，我使用https://social.technet.microsoft.com/wiki/contents/articles/31422.wpf-passing-a-data-bound-value-to-a-实现了它以validation-rule.aspx为例。

包装类 

public class HibernateConnectionWrapper : DependencyObject
{
    public static readonly DependencyProperty HibernateConnectorProperty =
         DependencyProperty.Register("hibernateConnector", typeof(HibernateConnector),
         typeof(HibernateConnectionWrapper), new FrameworkPropertyMetadata(null));

    public HibernateConnector hibernateConnector
    {
        get { return (HibernateConnector)GetValue(HibernateConnectorProperty); }
        set { SetValue(HibernateConnectorProperty, value); }
    }
}

绑定代理

public class BindingProxy : Freezable
{
    protected override Freezable CreateInstanceCore()
    {
        return new BindingProxy();
    }

    public object Data
    {
        get { return (object)GetValue(DataProperty); }
        set { SetValue(DataProperty, value); }
    }

    public static readonly DependencyProperty DataProperty =
        DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new PropertyMetadata(null));
}

验证类

public class EditRueckennummerValidationRule : ValidationRule
{
    public HibernateConnectionWrapper Wrapper { get; set; }

    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
    {
        bool n = Wrapper.hibernateConnector.isNullable(typeof(SpielerImTeam).FullName, "Rueckennummer");
        // ... more code

相关的 XAML 部分

<rcappbase:AbstractWorkAreaForm x:Class="mynamespace.TeamsForm"
  ...  
<DataGrid.Resources>
    <BindingProxy Data="{Binding}" x:Key="proxy"/>
</DataGrid.Resources>
<!-- other elements -->
<DataGridTextColumn Header="rueckennummer" IsReadOnly="False" DisplayIndex="5" >
    <DataGridTextColumn.Binding>
        <Binding Path="Rueckennummer" NotifyOnValidationError="True">
            <Binding.ValidationRules>
                <local:EditRueckennummerValidationRule>
                    <local:EditRueckennummerValidationRule.Wrapper>
                        <mynamespaceandassembly:HibernateConnectionWrapper  hibernateConnector="{Binding Path=Data.hibernateConnector, Source={StaticResource proxy}}"/>
                    </local:EditRueckennummerValidationRule.Wrapper>
                </local:EditRueckennummerValidationRule>
            </Binding.ValidationRules>  
        </Binding>
    </DataGridTextColumn.Binding>
</DataGridTextColumn>
<!-- more elements -->

我可以编译并运行代码，但在EditRueckennummerValidationRule.Validate(...)hibernateConnectorWrapper.hibernateConnector.isNullable(...) 中为 null。

那么我在这里做错了什么？它与 BindingProxy 有关吗（我看到的所有示例显然都具有相同的代码）？

4

1 回答 1

0

我需要一段时间来理解“数据上下文”，但我认为我同时解决了我自己的问题：

我搬家了

<DataGrid.Resources>
    <BindingProxy Data="{Binding}" x:Key="proxy"/>
</DataGrid.Resources>

至

<rcappbase:AbstractWorkAreaForm.Resources>
    <BindingProxy Data="{Binding }" x:Key="proxy"/>
</rcappbase:AbstractWorkAreaForm.Resources>

并添加了一行

public TeamsForm()
{
    InitializeComponent();
    DataContext = this; // <-- !!!! set the data context
}

我在上面引用的示例中错过了这一行！现在Wrapper.hibernateConnector是在验证方面设置的。

于 2018-07-22T12:53:07.497 回答