如何处理拖放而不违反MVVM主体？ [英] How to handle drag/drop without violating MVVM principals?

问题描述

目前我在我的XAML

Currently I have in my XAML

<TabControl  
    AllowDrop="True"
    PreviewDragOver="DragOver"
    PreviewDrop="Drop" />

我的所有拖放代码都存在于我的View代码中，而不是在我的ViewModel内。

All of my drag/drop code exists within the codebehind of my View, rather than within my ViewModel.

如何在ViewModel中处理拖放，而不在视图中添加任何依赖项？

How can I handle drag/drop in my ViewModel without adding any dependencies on the View?

推荐答案

有这样的图书馆，例如锣和类似的各种博客文章中的片段。

There are libraries for this such as gong and similar snippets on various blog articles.

但是，绝对没有代码隐藏，你不应该太挂起。例如，这本书仍然是MVVM：

However, you shouldn't get too hung up on having absolutely no code-behind. For example, this is still MVVM in my book:

void ButtonClicked(object sender, EventArgs e)
{
    ((MyViewModel) this.DataContext).DoSomething();
}

命令绑定可能是一个更好的选择，但逻辑肯定在视图模型。使用拖放功能，您可以在其中绘制线条更加变数。您可以在代码隐藏后解释Drag Args和调用方法在viewmodel适当时。

A command binding might be a better choice, but the logic is definitely in the viewmodel. With something like Drag and Drop, it's more variable where you want to draw the line. You can have code-behind interpret the Drag Args and call methods on the viewmodel when appropriate.

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