vue element 框架 自定义轮播图，点击上下翻图，并让图片居中

 1 <el-dialog class="material-dialog"
 2                    title="" 
 3                    :visible.sync="showMaterial"
 4                    width="50%" max-height="50%" top="10vh" center  :close-on-click-modal=false>
 5             <!-- <div v-if="this.materialList.length>1" class="arrow-left" @click="materialKeyEdit(-1)"><img src="../../assets/image/arrow-left.png" ></div> -->
 6             <div class="material-scroll" ref="material-scroll">
 7               <div class="material-left"  id="material-scroll">
 8                 <div class="material-box" v-for="(item,index) in materialList" :key="index"  @click="materialKeyEdit(index)" :class="{‘blue‘:index==materialKey}">
 9                     <div v-if="item.match(/((http|https):\/\/)/ig) && item.match(/((.jpg|.png|.gif))/ig)"><img style="max-width:100%;max-height:100%" class="" :src="item" > </div>
10                     <div v-else-if="item.match(/((http|https):\/\/)/ig) && item.match(/((.mp4|.rmvb|.rm|.3gp|.mov|.avi))/ig)"><video style="max-width:100%;max-height:100%" :src="item" ></video> </div>
11                     <div style="width:80%" v-else>{{item}}</div>
12                 </div>
13               </div>
14             </div>
15            <div class="material-right" style="" v-for="(item,index) in materialList" :key="index" v-show="index==materialKey">
16                 <div  class="arrow-left" @click="materialKeyAdd(-1)"><i class="el-icon-arrow-up"></i></div> 
17                 <div v-if="item.match(/((http|https):\/\/)/ig) && item.match(/((.jpg|.png|.gif))/ig)"><img class="" :src="item"  style="max-height:45vh"> </div>
18                 <div v-else-if="item.match(/((http|https):\/\/)/ig) && item.match(/((.mp4|.rmvb|.rm|.3gp|.mov|.avi))/ig)"><video style="max-height:45vh" :src="item"  controls="controls"></video> </div>
19                 <div v-else>{{item}}</div>
20                 <div   class="arrow-right" @click="materialKeyAdd(1)"><i class="el-icon-arrow-down"></i></div>
21                 <p style="text-align:center">{{index+1}} / {{materialList.length}}</p>
22            </div>
23            <!-- <div v-if="this.materialList.length>1"  class="arrow-right" @click="materialKeyEdit(1)"><img src="../../assets/image/arrow-right.png" ></div> -->
24         </el-dialog>

materialKeyEdit(num) {
      // console.log(this.materialKey)
     
      this.materialKey = num
    },
    materialKeyAdd(num){
      let box = this.$refs[‘material-scroll‘]
      // console.log(this.$refs[‘material-scroll‘])
      console.log(window.getComputedStyle(box).height)
      let px = window.getComputedStyle(box).height
      let height = Number(px.substring(0,px.length-2))
      console.log(height)
      let number = Math.round(height/150)
      console.log(number)
      // box.scrollTop = 500
      if(this.materialList.length>1){
        if (
          (this.materialKey == 0 && num > 0) ||
          (this.materialKey == this.materialList.length - 1 && this.materialList.length - 1>0 && num < 0) ||
          (this.materialKey > 0 &&
            this.materialKey < this.materialList.length - 1)
        ) {
          this.materialKey += num;
          if(this.materialKey<number || this.materialKey+(number +1) > this.materialList.length){
            if(this.materialKey<number){
              box.scrollTop = 0
            }
            if(this.materialKey+(number +1) > this.materialList.length){
              box.scrollTop = (this.materialList.length)*75
            }
            
          } else {
              box.scrollTop += 75*num
          }
        }
      }
    },