仅在使用鼠标时，如何允许拖放来排序项目？

Question

I'm trying to implement the drag-drop sort feature into my app and I'm having a little problem. Let's say I have something like this:

<ListView ItemsSource="{x:Bind ViewModel.Source, Mode=OneWay}"
          ScrollViewer.VerticalScrollBarVisibility="Auto"
          CanReorderItems="True"
          CanDragItems="True"
          AllowDrop="True"
          DragItemsStarting="MyList_DragItemsStarting"
          DragItemsCompleted="MyList_OnDragItemsCompleted"/>

I'm handling all the stuff I need from the DragItemsStarting and Completed events, and it all works fine.

The problem though is that I have some other code that is triggered when the user is using a touch screen (like swipe actions and stuff) and I want the drag/drop operation to only be available when using a mouse.

I'm not seeing a place where I can switch depending on the pointer device type, and I don't know where should I look.

Is there a way to do that? Has anyone implemented something like this and can explain how to code that?

Thank you for your help!

Sergio

Answer 1

You can use UIViewSettings class to get the current interaction mode, and enable or disable your wanted function for example like this:

switch (UIViewSettings.GetForCurrentView().UserInteractionMode)
{
    case UserInteractionMode.Mouse:
        listView.AllowDrop = true;
        listView.CanDragItems = true;
        listView.CanReorderItems = true;
        break;

    case UserInteractionMode.Touch:
    default:
        listView.AllowDrop = false;
        listView.CanDragItems = false;
        listView.CanReorderItems = false;
        break;
}

"listView" is the name of ListView which is defined in XAML code. You can use this code for example whenever the Point is over the ListView , or the Page is loaded or other time.

Answer 2

So there are many solutions for this. But why always reinvent the wheel. There is a cool library which you can use for your stuff.

So the GongSolutions.WPF.DragDrop library is a drag'n'drop framework for WPF and you can use it for ListView, ListBox or whatever ItemsControls.

<ListView ItemsSource="{Binding YourCollection}"
  dd:DragDrop.IsDragSource="True"
  dd:DragDrop.IsDropTarget="True"
  dd:DragDrop.DropHandler="{Binding}" />

It's MVVM ready and a sample demo is also there where you can see the library in action.

Hope that helps.