派生自 Binding 类 (Silverlight 4.0)
使用现有的 Binding 类，我们可以编写，
<TextBox Text="{Binding Email, Mode=TwoWay}"/>
因此我们可以将任何内容写为电子邮件； Binding 本身不进行有效性检查。我开始编写一个从 Binding 派生的类 BindingMore ，以便最终我可以编写，
<TextBox Text="{local:BindingMore Email, Validate=SomeMethod, Mode=TwoWay}"/>
其中 SomeMethod 是一些 ICommand 或delegate 将被触发以验证 Email 。这是我的目标，但我还没有写下来。
截至目前，我只编写了这段代码，
public class BindingMore : System.Windows.Data.Binding
{
public BindingMore() : base()
{
}
public BindingMore(string path) : base(path)
{
}
}
因此，在这个阶段， BindingMore 与 Binding 完全相同，但是当我编写时，
<TextBox Text="{local:BindingMore Email, Mode=TwoWay}"/>
它给了我运行时错误。但当我写的时候，
<TextBox Text="{local:BindingMore Path=Email, Mode=TwoWay}"/>
它工作得很好。谁能告诉我为什么在第一种情况下会出现运行时错误？
不幸的是，错误没有显示出来。它所显示的只是这样： 
另外，我从 XAML 收到以下错误消息（即使它完美构建并运行（在第二种情况下）） ）：
类型“local:BindingMore”的用法如下 标记扩展但不派生 来自标记扩展。
Using the existing Binding class, we can write,
<TextBox Text="{Binding Email, Mode=TwoWay}"/>
So we can write anything as Email; there is no validity check by Binding itself. I started writing a class BindingMore deriving from Binding so that eventually I could write,
<TextBox Text="{local:BindingMore Email, Validate=SomeMethod, Mode=TwoWay}"/>
Where SomeMethod is some ICommand or delegate which will be triggered to validate the Email . That is my objective, and I've not written that yet.
As of now, I've written just this code,
public class BindingMore : System.Windows.Data.Binding
{
public BindingMore() : base()
{
}
public BindingMore(string path) : base(path)
{
}
}
So, at this stage, BindingMore is exactly equivalent to Binding, yet when I write
<TextBox Text="{local:BindingMore Email, Mode=TwoWay}"/>
It's giving me runtime error. But when I write,
<TextBox Text="{local:BindingMore Path=Email, Mode=TwoWay}"/>
It's working fine. Can anybody tell me why it's giving runtime error in the first case?
Unfortunately, the error is not shown. All it shows is this:
Also, I get the following error message from XAML (even when it builds perfectly and runs (in the second case)):
Type 'local:BindingMore' is used like
a markup extension but does not derive
from MarkupExtension.
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Silverlight不支持自定义标记扩展。尝试使用附加属性方法或行为。Custom
Markup Extensionsare not supported inSilverlight. Try using anAttached Propertyapproach or aBehavior.