实现Inputnumber在focus时选中已有值。

src/components/input-number/input-number.vue

@@ -250,9 +250,9 @@
                     this.dispatch('FormItem', 'on-form-change', val);
                 });
             },
-            focus () {
+            focus (event) {
                 this.focused = true;
-                this.$emit('on-focus');
+                this.$emit('on-focus', event);
             },
             blur () {
                 this.focused = false;