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)?