添加项目文件。

Sai.Toolkit.Mvvm/Behaviors/DropFileBehavior.cs

@@ -0,0 +1,45 @@
+
+using System.Windows;
+
+using Microsoft.Xaml.Behaviors;
+
+/// <summary>
+/// 拖拽文件事件
+/// </summary>
+/// <example>DropFileBehaviors Data="{Binding FileNames,Mode=OneWayToSource}"从依赖属性传到源属性，通过源属性实现Mvvm</example>
+/// <remarks>设置窗口属性AllowDrop，在上层覆盖一个面板如Grid，设置窗口的DropEnter和DropLeave(EventTrigger)事件，控制其显隐以及控制Drop事件后隐藏(ChangePropertyAction)</remarks>
+class DropFileBehavior : Behavior<FrameworkElement>
+{
+    public string[] Data
+    {
+        get { return (string[])GetValue(DataProperty); }
+        set { SetValue(DataProperty, value); }
+    }
+
+    public static readonly DependencyProperty DataProperty =
+        DependencyProperty.Register(nameof(Data), typeof(string[]), typeof(DropFileBehavior), new PropertyMetadata(null));
+
+
+    protected override void OnAttached()
+    {
+        AssociatedObject.AllowDrop = true;
+        AssociatedObject.Drop += DropHandler;
+    }
+
+    private void DropHandler(object sender, DragEventArgs e)
+    {
+        if (e.Data.GetDataPresent(DataFormats.FileDrop))
+        {
+            Data = (string[])e.Data.GetData(DataFormats.FileDrop);
+        }
+    }
+
+    protected override void OnDetaching()
+    {
+        AssociatedObject.Drop -= DropHandler;
+    }
+    protected override void OnChanged()
+    {
+        base.OnChanged();
+    }
+}