add NPC list changed event (#310)

2 files changed, 41 insertions, 0 deletions

diff --git a/src/SMAPI/Events/IWorldEvents.cs b/src/SMAPI/Events/IWorldEvents.cs
index 7ec26bae..ce288ae1 100644
--- a/src/SMAPI/Events/IWorldEvents.cs
+++ b/src/SMAPI/Events/IWorldEvents.cs
@@ -14,6 +14,9 @@ namespace StardewModdingAPI.Events
         /// <summary>Raised after buildings are added or removed in a location.</summary>
         event EventHandler<WorldBuildingListChangedEventArgs> BuildingListChanged;
 
+        /// <summary>Raised after NPCs are added or removed in a location.</summary>
+        event EventHandler<WorldNpcListChangedEventArgs> NpcListChanged;
+
         /// <summary>Raised after objects are added or removed in a location.</summary>
         event EventHandler<WorldObjectListChangedEventArgs> ObjectListChanged;
 
diff --git a/src/SMAPI/Events/WorldNpcListChangedEventArgs.cs b/src/SMAPI/Events/WorldNpcListChangedEventArgs.cs
new file mode 100644
index 00000000..e251f894
--- /dev/null
+++ b/src/SMAPI/Events/WorldNpcListChangedEventArgs.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using StardewValley;
+
+namespace StardewModdingAPI.Events
+{
+    /// <summary>Event arguments for a <see cref="IWorldEvents.NpcListChanged"/> event.</summary>
+    public class WorldNpcListChangedEventArgs : EventArgs
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The location which changed.</summary>
+        public GameLocation Location { get; }
+
+        /// <summary>The NPCs added to the location.</summary>
+        public IEnumerable<NPC> Added { get; }
+
+        /// <summary>The NPCs removed from the location.</summary>
+        public IEnumerable<NPC> Removed { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="location">The location which changed.</param>
+        /// <param name="added">The NPCs added to the location.</param>
+        /// <param name="removed">The NPCs removed from the location.</param>
+        public WorldNpcListChangedEventArgs(GameLocation location, IEnumerable<NPC> added, IEnumerable<NPC> removed)
+        {
+            this.Location = location;
+            this.Added = added.ToArray();
+            this.Removed = removed.ToArray();
+        }
+    }
+}