How to develop tree components using Vue

This article mainly introduces the sample code for developing Vue tree components, which shows the recursive use of components. Now I share it with you and give it as a reference.

This article introduces the sample code of the Vue tree component and shares it with everyone. The details are as follows:

Use SemanticUI and vue to make a menubar component. The implementation method is roughly as follows:

<template> 
  <p class="ui menu"> 
   <template v-for="item in leftItems"> 
    <a " v-if="!item.children" @click="item.click"> 
     <i class="{{ item.icon }} icon" v-if="item.icon"></i>{{item.text}} 
     <p class="ui mini {{item.labelColor }} label" v-if="item.label"> 
      {{item.label}} 
     </p> 
    </a>  
   //如果有有children则说明是下拉菜单项，然后递归调用自身 
    <template v-else="item.children.length > 0"> 
     <p class="ui dropdown item"> 
      <i class="{{ item.icon }} icon" v-if="item.icon"></i>   
      <p class="text"> {{item.text}}</p> 
      <menubar :items="item.children" ></menubar> 
     </p> 
    </template> 
   </template> 
  //显示在右侧的菜单项，也是递归调用自身 
   <menubar :items="rightItems" v-if="rightItems.length > 0"></menubar> 
  </p> 
</template>

When using, if the parent component app uses the menubar component, then the items data needs to be defined in the data. For example:

menubar:[ 
     {id:"a",text:"主页1",icon:"home",tips:"提示",label:"33",labelColor:"red",url:"#"}, 
     {id:"b",text:"菜单",icon:"edit",tips:"提示",url:"#",children:[ 
       {id:"a",text:"菜单1",click:"test3",icon:"home",url:"#"}, 
       {id:"a",text:"菜单2",click:"test3",icon:"home",url:"#"} 
     ]}, 
     {id:"bb",text:"编辑",tab:"a",icon:"user",vlink:"#"}, 
     {id:"bb",text:"文件",tab:"b",icon:"user",click:"test1"}, 
     {id:"bb",text:"帮助",tab:"c",icon:"help",click:"test2"}, 
     {id:"bb",text:"工具",icon:"user",url:"www.baidu.com"}, 
     {id:"c",text:"设置",icon:"home",tips:"提示",enabled:true,color:"blue",url:"#",right:true,label:"",children:[ 
        {id:"bbb",text:"配置",icon:"home",tips:"提示",click:"test3"}, 
        {id:"adsd",text:"退出",icon:"home",tips:"提示",vlink:"/workdesk",url:"#"} 
        ] 
      } 
   ]

The click event in

events:{ 
  eventa:function(){....}, 
  eventb:function(){....}, 
}

is defined when the toolbar is clicked. Events, ideally should be defined in the events of the parent component app, like this:

<a @click="onMenuItemClick(item,$event)" data-tab="{{item.tab}}" v-link="item.vlink" href="{{item.url}}" rel="external nofollow" v-if="!item.children" :class="[{&#39;active&#39;:item.active==true,&#39;disabled&#39;:item.enabled==false},item.color,&#39;item&#39;]" title="{{item.tips}}"> 
     <i class="{{ item.icon }} icon" v-if="item.icon"></i>{{item.text}} 
     <p class="ui mini {{item.labelColor }} label" v-if="item.label"> 
      {{item.label}} 
     </p> 
    </a>

The toolbar component is generated based on the incoming items, including the child components inside. The structure of the final toolbar component is a tree structure, for example:

MenuBar
--MenuBar                                                                                            --Menubar

Since each Menubar in each toolbar component has its own context, when the click event of the sub-component Menubar is triggered, the event defined in the top-level app component events will not be called. Instead, it just calls the events of the parent Menubar.

But in terms of user experience, it is obvious that the click event definition of the toolbar component should be defined in the events of the app component. We hope that when menubar:[] defines a menu item, no matter how many levels of nesting it is, the triggering of the event can bubble up to the parent of the top menubar.

Therefore, to implement this mechanism, the communication mechanism between components is currently used:

methods:{ 
  onMenuItemClick:function(item,$event){    
   if(this.subMenu){ 
    this.$dispatch("menuItemClick",item,$event)  
   }else{ 
    if(item.click){ 
     this.$parent.$emit(item.click,item) 
    } 
   }   
  } 
 }

The above defines an event @click="onMenuItemClick(item,$event)"

events:{ 
  menuItemClick:function(item,$event){ 
   if(!this.subMenu){ 
    this.$parent.$emit(item.click,item) 
   }else{ 
    return true 
   } 
  } 
 },

When onMenuItemClick is triggered, we confirm how the click event is processed based on the incoming subMenu. If the Menubar is processed as a submenu bar, we will directly bubble the event upward, otherwise the event will be triggered in the upper parent component.

Copy code The code is as follows:

When calling inside the menubar component, pass in submenu=true, and listen for the event menuItemClick. The menuItemClick event code is as follows:

<MenuBar> 
 <button scoped="false"></button> 
<button scoped="false"></button> 
</MenuBar>

To summarize:

When dealing with components with nested structures, such as toolbars with drop-down menus, tree components, etc., since each component has its own independent context, it must Use the component communication mechanism to handle communication between internal components.

But I think this way of handling it is still troublesome. Ideally, I think the best official way can provide a mechanism for the component to directly use the context of the parent component, for example:

rrreee

In this way, the button above does not have its own context, but can directly introduce the context of the parent component. This pattern should be used in many situations.

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

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