[issues/5003]表单开发j-category-select placeholder不显示问题

src/components/Form/src/jeecg/components/JCategorySelect.vue

@@ -71,7 +71,7 @@
         required: false,
       },
     },
-    emits: ['options-change', 'change'],
+    emits: ['options-change', 'change', 'update:value'],
     setup(props, { emit, refs }) {
       console.info(props);
       const emitData = ref<any[]>([]);
@@ -122,7 +122,7 @@
           if(props.multiple){
             treeValue.value = [];
           }else{
-            treeValue.value = '';
+            treeValue.value = null;
           }
         } else {
           loadDictItem({ ids: props.value }).then((res) => {
@@ -153,6 +153,7 @@
           obj[props.back] = label;
         }
         emit('change', value, obj);
+        emit("update:value",value)
       }
 
       function asyncLoadTreeData(treeNode) {
@@ -205,6 +206,7 @@
         if (!value) {
           emit('change', '');
           treeValue.value = '';
+          emit("update:value",'')
         } else if (Array.isArray(value)) {
           let labels = [];
           let values = value.map((item) => {