WPF / Silverlight / XAML中的强类型数据绑定？

我最大的宠物小狗之一，如何使用XAML进行数据绑定是没有任何选择来强烈地键入数据绑定。换句话说，在C＃中，如果要访问不存在的对象上的属性，则不会从Intellisense得到任何帮助，如果您坚持忽略Intellisense，编译器将会抓住您并赢得让你继续 - 我怀疑这里的很多人都会同意这是一个非常好的事情。但是，在XAML数据绑定中，您正在运行没有网络。即使不存在，也可以绑定到任何。实际上，考虑到XAML数据绑定的奇怪语法，并给出了我自己的经验，绑定到存在的东西比不存在的东西要复杂得多。我更有可能使我的数据绑定语法错误，而不是正确;而我花费在XAML数据库中排除故障的比较时间容易使我与微软堆栈的任何其他部分（包括尴尬和令人讨厌的WCF，如果你能相信）花费的时间相差无几。而且大部分（并不是全部）回到了没有强类型数据绑定的事实，我无法从Intellisense或编译器获得任何帮助。

One of my biggest pet peeves with how databinding works with XAML is that there's no option to strongly type your databindings. In other words, in C#, if you want to access a property on an object that doesn't exist, you won't get any help from Intellisense, and if you insist on ignoring Intellisense, the compiler will gripe at you and won't let you proceed -- and I suspect that lots of folks here would agree that this is a Very Good Thing. But in XAML databinding, you're operating without a net. You can bind to anything, even if it doesn't exist. Indeed, given the bizarre syntax of XAML databinding, and given my own experience, it's a great deal more complicated to bind to something that does exist than to something that doesn't. I'm much more likely to get my databinding syntax wrong than to get it right; and the comparative time I spend troubleshooting XAML databindings easily dwarfs the time I spend with any other portion of Microsoft's stack (including the awkward and annoying WCF, if you can believe it). And most of that (not all of it) goes back to the fact that without strongly-typed databindings, I can't get any help from either Intellisense or the compiler.

所以我想知道的是：为什么MS至少给我们一个选项有强类型的数据绑定：有点像VB6中的一样，如果我们真的很疯狂，但大多数时候使用正常类型的变量是有意义的。有没有什么原因MS不能这样做？

So what I want to know is: why doesn't MS at least give us an option to have strongly-typed databindings: kind of like how in VB6, we could make any object a variant if we were really masochistic, but most of the time it made sense to use normal, typed variables. Is there any reason why MS couldn't do that?

这是一个我的意思的例子。在C＃中，如果属性UsrID不存在，您会收到Intellisense的警告和编译器的错误，如果您尝试这样做：

Here's an example of what I mean. In C#, if the property "UsrID" doesn't exist, you'll get a warning from Intellisense and an error from the compiler if you try this:

string userID = myUser.UsrID;

但是，在XAML中，您可以这样做：

However, in XAML, you can do this all you want:

<TextBlock Text="{Binding UsrID}" />

在运行时，Intellisense，编译器或（最惊人的）应用程序本身都不会给你任何提示你做错了事情。现在，这是一个简单的例子，但是处理复杂对象图和复杂UI的任何真实应用程序都将具有很多等同的场景，这些方案根本不简单，也不易于排除故障。即使您已经第一次正常工作，您也是SOL，如果您重构代码并更改C＃属性名称。一切都将编译，它会运行没有错误，但没有任何工作，让您通过整个应用程序狩猎和啄钻，试图弄清楚是什么。

And neither Intellisense, the compiler, or (most astonishingly) the application itself at runtime will give you any hint that you've done something wrong. Now, this is a simplistic example, but any real-world application that deals with complex object graphs and complex UI's is going to have plenty of equivalent scenarios that aren't simple at all, nor simple to troubleshoot. And even after you've gotten it working correctly the first time, you're SOL if you refactor your code and change your C# property names. Everything will compile, and it'll run without an error, but nothing will work, leaving you to hunt and peck your way through the entire application, trying to figure out what's broken.

一个可能的建议（我的头顶，我没有想过）可能是这样的：

One possible suggestion (off the top of my head, and which I haven't thought through) would maybe be something like this:

对于逻辑树，您可以在XAML中指定它期望的对象的DataType，如下所示：

For any portion of the logical tree, you could specify in XAML the DataType of the object that it's expecting, like so:

<Grid x:Name="personGrid" BindingDataType="{x:Type collections:ObservableCollection x:TypeArgument={data:Person}}">

这可能会生成一个强类型的ObservableCollection< Person> .g.cs文件中的TypedDataContext属性。所以在你的代码中：

This would perhaps generate a strongly-typed ObservableCollection<Person> TypedDataContext property in the .g.cs file. So in your code:

// This would work
personGrid.TypedDataContext = new ObservableCollection<Person>(); 

// This would trigger a design-time and compile-time error
personGrid.TypedDataContext = new ObservableCollection<Order>(); 

如果您通过网格上的控件访问该TypedDataContext，它会知道什么样的

And if you then accessed that TypedDataContext through a control on the grid, it would know what sort of an object you were trying to access.

<!-- It knows that individual items resolve to a data:Person -->
<ListBox ItemsSource="{TypedBinding}">
    <ListBox.ItemTemplate>
       <DataTemplate>
           <!--This would work -->
           <TextBlock Text="{TypedBinding Path=Address.City}" />
           <!-- This would trigger a design-time warning and compile-time error, since it has the path wrong -->
           <TextBlock Text="{TypedBinding Path=Person.Address.City} />
       </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

我发布了一个博客

I've made a blog posting here that explains more about my frustrations with WPF/XAML databinding, and what I think would be a significantly better approach. Is there any reason why this couldn't work? And does anyone know if MS is planning to fix this problem (along the lines of my proposal, or hopefully, a better one)?