WPF 无法将数据绑定(bind)到接口(interface)？

Question

我尝试将 WPF 表单中的控件绑定(bind)到接口(interface)，但收到运行时错误，指出找不到接口(interface)的属性。

这是我用作数据源的类:

public interface IPerson
{
    string UserId { get; set; }
    string UserName { get; set; }
    string Email { get; set; }
}

public class Person : EntityBase, IPerson
{
    public virtual string UserId { get; set; }
    public string UserName { get; set; }
    public virtual string Email { get; set; }
}

这是 XAML(摘录):

<TextBox Name="userIdTextBox" Text="{Binding UserId}" />
<TextBox Name="userNameTextBox" Text="{Binding UserName}" />
<TextBox Name="emailTextBox" Text="{Binding Email}" />

这是背后的代码(再次摘录):

var person = PolicyInjection.Wrap<IPerson>(new Person());
person.UserId = "jdoe";
person.UserName = "John Doe";
person.Email = "<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="402a242f25002c2936256e232f2d" rel="noreferrer noopener nofollow">[email protected]</a>";

this.DataContext = person;

请注意，我用作数据源的类需要是一个实体，因为我通过 entlib 的策略注入(inject)应用程序 block 使用策略注入(inject)。

我在运行时收到此错误:

System.Windows.Data Error: 16 : Cannot get 'Email' value (type 'String') from '' (type 'Person'). BindingExpression:Path=Email; DataItem='Person' (HashCode=22322349); target element is 'TextBox' (Name='emailTextBox'); target property is 'Text' (type 'String') TargetException:'System.Reflection.TargetException: Object does not match target type.
   at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, BindingFlags invokeAttr, Binder binder, Object[] index, CultureInfo culture)
   at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
   at MS.Internal.Data.PropertyPathWorker.GetValue(Object item, Int32 level)
   at MS.Internal.Data.PropertyPathWorker.RawValue(Int32 k)'

Answer 1

我不熟悉 entlib 的策略注入(inject)，但我很确定你的问题就在那里，而不是因为你正在使用接口(interface)。
如果你要替换

var person = PolicyInjection.Wrap<IPerson>(new Person());

与

IPerson person = new Person();

这肯定有用吗？