add searchbar

HandyControl/Interactivity/ControlCommands.cs

@@ -7,6 +7,11 @@ namespace HandyControl.Interactivity
     /// </summary>
     public static class ControlCommands
     {
+        /// <summary>
+        ///     搜索
+        /// </summary>
+        public static RoutedCommand Search { get; } = new RoutedCommand(nameof(Search), typeof(ControlCommands));
+
         /// <summary>
         ///     清除
         /// </summary>