WPF和MVVM。结合事件 [英] WPF and MVVM. Binding Events
问题描述
我发展与MVVM模式，RelayCommand等WPF应用程序
我读了关于这个问题有很多，但我并不清楚：
I'm developing a WPF application with the MVVM pattern, RelayCommand, etc. I read a lot on this question but I am not clear as to:
所有我想要做的是移动形状，像一个椭圆形，例如，抢占其最终位置，将在数据库中。
All I want to do is move a shape, like an ellipse, for example, and capture its final position, to put in the database.
但我不能绑定事件（MouseLetButtonDown，和的MouseLeftButtonUp的MouseMove）的命令。我读过有关附加的行为，但我需要的事件（MouseButtonEventArgs和MouseEventArgs）的参数来检索位置。
But I can't bind events (MouseLetButtonDown, MouseLeftButtonUp and MouseMove) to commands. I've read about attached behaviours , but I need the arguments of the events (MouseButtonEventArgs and MouseEventArgs) to retrieve the position.
解决方案？
推荐答案
当编写一个MVVM图形应用程序，这是很有诱惑力的尝试发送你需要切换到视图模型的所有事件。但是，在一个命令处理视图特定的鼠标事件参数违反MVVM原则和松耦合的目标。
When writing an MVVM graphical application, it is tempting to try to send all the events you need over to the view-model. But processing view-specific mouse event args in a command is contrary to MVVM principles and the goal of loose-coupling.
要解决这个问题的方法是抽象操作进入该视图可以执行，然后进行通信的结果反馈给通过操作和数据的视图模型的任务。如果你想在code-后面执行code少量支持这一点，MVVM警方不会来照顾你的孩子。但更好的方法是用行为增加互动性。行为是可重复使用的功能件，没有code-身后MVVM模式和需要交互性，否则将需要添加事件处理你的XAML应用程序工作做好。
The way to solve this problem is to abstract the operation into a task that the view can perform and then to communicate its results back to the view-model via operations and data. If you want to perform a small amount of code in the code-behind to support this, the MVVM police will not come and take your children. But an even better way is to add interactivity with behaviors. Behaviors are re-usable pieces of functionality with no code-behind that work well with the MVVM pattern and applications that need interactivity that would otherwise require adding event handlers to your XAML.
请参阅我的答案在这里，它使用的鼠标事件拖动图形对象行为的完整例子：
See my answer here for a complete example of a behavior that uses mouse events for dragging graphical objects:
- Coach a newbie through basic WPF? (I Do Not Grok It.)
由视图下的互动，视图模型能够坚持数据和命令。
With your interactivity performed by the view, the view-model can stick to data and commands.
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