updated

Author: flocked

Example/Example.xcodeproj/project.pbxproj

@@ -136,8 +136,8 @@
 			children = (
 				72AFC23929804B7D00FEA1C8 /* CollectionItem.swift */,
 				72F99B672A44FBDD00DDDA1E /* SidebarItem.swift */,
-				72F99B652A44FBCB00DDDA1E /* Section.swift */,
 				726BE2692D3DB14C00823E9B /* OutlineItem.swift */,
+				72F99B652A44FBCB00DDDA1E /* Section.swift */,
 			);
 			path = Model;
 			sourceTree = "<group>";

Example/Example/MainViewController.swift

@@ -77,26 +77,6 @@ class MainViewController: NSViewController {
 
         dataSource.selectElements([galleryItems.first!], scrollPosition: .top)
         collectionView.makeFirstResponder()
-        
-        Swift.print(NSDiffableDataSourceSnapshotReference.classReflection())
-        var object = dataSource.snapshot() as NSDiffableDataSourceSnapshotReference
-        object.perform(NSSelectorFromString("reconfigureItemsWithIdentifiers:"), with: [galleryItems[0], galleryItems[1]])
-        if let impl: NSObject = object.getIvarValue(for: "_impl") {
-            Swift.print(impl.objectIdentifier)
-            if let reconfiguredItemIdentifiers = impl.value(forKey: "reconfiguredItemIdentifiers") as? [GalleryItem] {
-                Swift.print(reconfiguredItemIdentifiers)
-            }
-        }
-        let snapshot = object as NSDiffableDataSourceSnapshot<Section, GalleryItem>
-        object = snapshot as NSDiffableDataSourceSnapshotReference
-        if let impl: NSObject = object.getIvarValue(for: "_impl") {
-            Swift.print(impl.objectIdentifier)
-
-            if let reconfiguredItemIdentifiers = impl.value(forKey: "reconfiguredItemIdentifiers") as? [GalleryItem] {
-                Swift.print(reconfiguredItemIdentifiers)
-            }
-        }
-        
     }
 
     func applySnapshot(using items: [GalleryItem]) {

Example/Example/Model/OutlineItem.swift

@@ -7,18 +7,19 @@
 
 import Foundation
 
-struct OutlineItem: Hashable, ExpressibleByStringLiteral, CustomStringConvertible {
-    let title: String
+public struct OutlineItem: Hashable, ExpressibleByStringLiteral, CustomStringConvertible {
 
-    init(_ title: String) {
+    public let title: String
+    
+    public init(_ title: String) {
         self.title = title
     }
 
-    init(stringLiteral value: String) {
+    public init(stringLiteral value: String) {
         self.title = value
     }
 
-    var description: String {
+    public var description: String {
         title
     }
 }

Example/Example/Model/SidebarItem.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-class SidebarItem: NSObject, Identifiable {
+public class SidebarItem: NSObject, Identifiable {
 
     public let title: String
     public let symbolName: String

Example/Example/OutlineSidebarViewController.swift

@@ -12,16 +12,11 @@ class OutlineSidebarViewController: NSViewController {
     typealias DataSource = OutlineViewDiffableDataSource<OutlineItem>
     typealias CellRegistration = NSTableView.CellRegistration<NSTableCellView, OutlineItem>
 
-
     @IBOutlet var outlineView: NSOutlineView!
 
     lazy var dataSource = DataSource(outlineView: outlineView, cellRegistration: cellRegistration)
 
-    var currentSnapshot: OutlineViewDiffableDataSourceSnapshot<OutlineItem> {
-        dataSource.snapshot()
-    }
-
-    lazy var cellRegistration = CellRegistration { tableCell, _, _, outlineItem in
+    let cellRegistration = CellRegistration { tableCell, _, _, outlineItem in
         var configuration = tableCell.defaultContentConfiguration()
         configuration.text = outlineItem.title
         tableCell.contentConfiguration = configuration

Example/Example/TableSidebarViewController.swift

@@ -46,6 +46,16 @@ class TableSidebarViewController: NSViewController {
         /// Enables deleting selected rows via backspace key.
         dataSource.deletingHandlers.canDelete = { selectedItems in return selectedItems  }
 
+        /// Enable dropping strings to the table view by checking if the drop contains strings.
+        dataSource.droppingHandlers.canDrop = { drop in
+            return !drop.content.strings.isEmpty
+        }
+        
+        /// Provides sidebar items for the dropped strings.
+        dataSource.droppingHandlers.items = { drop in
+            return drop.content.strings.compactMap({ SidebarItem($0, symbolName: "photo") })
+        }
+        
         /// Swipe row actions for deleting and favoriting an item.
         dataSource.rowActionProvider = { swippedItem, edge in
             if edge == .leading {