添加项目文件。

Live-Charts-master/Examples/Wpf/PieChart/DropDowns/DropDownCommand.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Windows.Input;
+using LiveCharts;
+
+namespace Wpf.PieChart.DropDowns
+{
+    public class DropDownCommand : ICommand
+    {
+        private Action<DropDownPoint> _action;
+
+        public DropDownCommand(Action<DropDownPoint> action)
+        {
+            _action = action;
+        }
+
+        public void Execute(object parameter)
+        {
+            var chartPoint = (ChartPoint) parameter;
+            var dropDownPoint = (DropDownPoint) chartPoint.Instance;
+
+            _action(dropDownPoint);
+        }
+
+        public bool CanExecute(object parameter)
+        {
+            return true;
+        }
+
+        public event EventHandler CanExecuteChanged;
+    }
+}