npm install vuedraggable --save

import vue from 'vue';
 
// v-dialogdrag: 弹窗拖拽属性
vue.directive('dialogdrag', {
    bind(el, binding, vnode, oldvnode) {
        const dialogheaderel = el.queryselector('.el-dialog__header');
        const dragdom = el.queryselector('.el-dialog');
 
        dialogheaderel.style.csstext += ';cursor:move;'
        dragdom.style.csstext += ';top:0px;'
 
        // 获取原有属性 ie dom元素.currentstyle 火狐谷歌 window.getcomputedstyle(dom元素, null);
        const sty = (() => {
            if (window.document.currentstyle) {
                return (dom, attr) => dom.currentstyle[attr];
            } else {
                return (dom, attr) => getcomputedstyle(dom, false)[attr];
            }
        })()
 
        dialogheaderel.onmousedown = (e) => {
            // 鼠标按下，计算当前元素距离可视区的距离
            const disx = e.clientx - dialogheaderel.offsetleft;
            const disy = e.clienty - dialogheaderel.offsettop;
 
            const screenwidth = document.body.clientwidth; // body当前宽度
            const screenheight = document.documentelement.clientheight; // 可见区域高度(应为body高度，可某些环境下无法获取)
 
            const dragdomwidth = dragdom.offsetwidth; // 对话框宽度
            const dragdomheight = dragdom.offsetheight; // 对话框高度
 
            const mindragdomleft = dragdom.offsetleft;
            const maxdragdomleft = screenwidth - dragdom.offsetleft - dragdomwidth;
 
            const mindragdomtop = dragdom.offsettop;
            const maxdragdomtop = screenheight - dragdom.offsettop - dragdomheight;
 
 
            // 获取到的值带px 正则匹配替换
            let styl = sty(dragdom, 'left');
            let styt = sty(dragdom, 'top');
 
            // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
            if (styl.includes('%')) {
                styl = +document.body.clientwidth * (+styl.replace(/\%/g, '') / 100);
                styt = +document.body.clientheight * (+styt.replace(/\%/g, '') / 100);
            } else {
                styl = +styl.replace(/\px/g, '');
                styt = +styt.replace(/\px/g, '');
            };
 
            document.onmousemove = function (e) {
                // 通过事件委托，计算移动的距离
                let left = e.clientx - disx;
                let top = e.clienty - disy;
 
                // 边界处理
                if (-(left) > mindragdomleft) {
                    left = -(mindragdomleft);
                } else if (left > maxdragdomleft) {
                    left = maxdragdomleft;
                }
 
                if (-(top) > mindragdomtop) {
                    top = -(mindragdomtop);
                } else if (top > maxdragdomtop) {
                    top = maxdragdomtop;
                }
 
                // 移动当前元素 
                dragdom.style.csstext += `;left:${left + styl}px;top:${top + styt}px;`;
            };
 
            document.onmouseup = function (e) {
                document.onmousemove = null;
                document.onmouseup = null;
            };
        }
    }
})

<el-dialog
    v-dialogdrag
    :title="dialogtitle"
    :visible.sync="adddialogvisible"
    :before-close="handleclose"
    :close-on-click-modal="false"
    width="50%">
    <div class="add_columns">
        <div class="pull-organize">
            <div class="bm-title">部门管理</div>
            <el-tree
                :data="treedata"
                lazy:load="loadnode"
                accordion 
                :props="defaultprops"
                :default-expand-all="false">
            </el-tree>
        </div>
        <div class="show-information">
            <el-form inline>
                <el-form-item label="用户id">
                    <el-input v-model="searchparams.userid" size="mini" ></el-input>
                </el-form-item>
                <el-form-item label="用户名">
                    <el-input v-model="searchparams.username" size="mini"></el-input>
                </el-form-item>
                <el-form-item class="btn-item">
                    <el-button type="primary" @click="handlequery" size="mini">查询</el-button>
                </el-form-item>
                    <el-form-item class="btn-item">
                    <el-button type="success" @click="hadnleaddperson" size="mini">添加人员</el-button>
                </el-form-item>
            </el-form>
            <el-table
                :data="tabledata"
                class="onetabel"
                style="width:100%;">
                <el-table-column type="selection" width="50"></el-table-column>
                <el-table-column prop="id" width="60" label="登录id"></el-table-column>
                <el-table-column prop="username" label="用户名"></el-table-column>
                <el-table-column prop="education" label="部门"></el-table-column>
                <el-table-column prop="sex" label="手机"></el-table-column>
            </el-table>
        </div>
    </div>
</el-dialog>