[WPF] 외부파일 Drag & Drop

 

 

 

xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
xmlns:behavior="clr-namespace:SampleProject.ViewModel.Behavior"

<Grid AllowDrop="True">
<!--Drag & Drop 할 공간-->
</Grid>

<Grid AllowDrop="True">
    <i:Interaction.Behaviors>
        <behavior:FileDropBehavior DroppedFiles="{Binding DroppedFiles, Mode=TwoWay}"/>
    </i:Interaction.Behaviors>
</Grid>

 

class FileDropBehavior : Behavior<FrameworkElement>
{
    public static readonly DependencyProperty DroppedFilesProperty = DependencyProperty.Register("DroppedFiles", typeof(string[]), typeof(FileDropBehavior), new PropertyMetadata(default(string[])));
    public string[] DroppedFiles
    {
        get { return (string[])GetValue(DroppedFilesProperty); }
        set { SetValue(DroppedFilesProperty, value); }
    }

    protected override void OnAttached()
    {
        AssociatedObject.Drop += AssociatedObjectDrop;
    }

    private void AssociatedObjectDrop(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(DataFormats.FileDrop))
        {
            DroppedFiles = (string[])e.Data.GetData(DataFormats.FileDrop);
        }
    }

    protected override void OnDetaching()
    {
        AssociatedObject.Drop -= AssociatedObjectDrop;
    }
}

 

 

 

AssociatedObject.DragEnter

DragLeave

DragOver

할 때 

e.Handled = true; 줘야 적용 됨.

 

 

 

---

변경 된  e 를 적용하기 위해서는

e.Handled를 해야 적용 됨.

ex)

아래 files is null이라서 retrurn 할 경우 

e.Effects = DragDropEffects.None;

적용이 안된 상태로 끝남.

 

 

return 전에 

e.Handled = true;

적용해야 함.

---

 

https://nonstop-antoine.tistory.com/103

[WPF] File Drag & Drop MVVM Pattern using Behavior

 

 

https://learn.microsoft.com/en-us/dotnet/desktop/wpf/advanced/drag-and-drop-overview?view=netframeworkdesktop-4.8&viewFallbackFrom=netdesktop-9.0

Drag and Drop Overview - WPF .NET Framework

 

 

https://stackoverflow.com/questions/44319258/wpf-drag-drop-none-effect-not-triggering

WPF drag drop none effect not triggering