add extension method to move an item within an collection

Pilz.Extensions/Collections/IListExtensions.cs

@@ -0,0 +1,30 @@
+namespace Pilz.Extensions.Collections;
+
+public static class IListExtensions
+{
+    public static bool Move<T>(this IList<T> @this, T item, int amount)
+    {
+        var oldIndex = @this.IndexOf(item);
+
+        if (oldIndex == -1)
+            return false;
+
+        var newIndex = oldIndex + amount;
+
+        if (newIndex < 0)
+            newIndex = 0;
+        else if (newIndex >= @this.Count)
+            newIndex = @this.Count;
+
+        if (newIndex == oldIndex)
+            return false;
+
+        if (newIndex > 0 && newIndex > oldIndex)
+            newIndex -= 1;
+
+        @this.RemoveAt(oldIndex);
+        @this.Insert(newIndex, item);
+
+        return true;
+    }
+}