如何使用ElementUI创建可拖动的Dialog弹窗并限制其离开屏幕、移动大小？

• 完美版:

可以实现拖拽移动位置，水平垂直缩放，对角线缩放 ,禁止拖出屏幕

yyds!

• 关注点赞使用哟，持续更新前端好文~

【src\utils\directives.js】

// v-dialog-drag-and-zoom: 弹窗拖拽+水平垂直对角线方向伸缩
Vue.directive('dialogDragAndZoom', {
    bind(el, binding, vnode, oldVnode) {
      //弹框可拉伸最小宽高
      let minWidth = 250;
      let minHeight = 200;
      //初始非全屏
      let isFullScreen = false;
      //当前宽高
      let nowWidth = 0;
      let nowHight = 0;
      //当前顶部高度
      let nowMarginTop = 0;
      //获取弹框头部（这部分可双击全屏）
      const dialogHeaderEl = el.querySelector('.el-dialog__header');
      //弹窗
      const dragDom = el.querySelector('.el-dialog');
      //给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；
      dragDom.style.overflow = "auto";
      //清除选择头部文字效果
      dialogHeaderEl.onselectstart = new Function("return false");  
      //头部加上可拖动cursor
      dialogHeaderEl.style.cursor = 'move';
      // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
      const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);
      let moveDown = (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;
        // 获取到的值带px 正则匹配替换
        let styL, styT;
        // 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 (sty.left.includes('%')) {
          styL = +document.body.clientWidth * (+sty.left.replace(/%/g, '') / 100);
          styT = +document.body.clientHeight * (+sty.top.replace(/%/g, '') / 100);
        } else {
          styL = +sty.left.replace(/px/g, '');
          styT = +sty.top.replace(/px/g, '');
        }
        const bodyWidth = document.body.clientWidth
        const bodyHeight = document.body.clientHeight // 获取屏幕高度
        document.onmousemove = function (e) {
          // 通过事件委托，计算移动的距离 
          const l = e.clientX - disX;
          const t = e.clientY - disY;
          // console.log("鼠标移动到的位置",e.clientX, e.clientY)

          // 限制不让拖出屏幕 *****
          if(e.clientY<20 || e.clientY > bodyHeight -100){
            return 
          }
          if(e.clientX<100 || e.clientX > bodyWidth -100){
            return 
          }

        // 移动当前元素  
          dragDom.style.left = `${l + styL}px`;
          dragDom.style.top = `${t + styT}px`;
          //将此时的位置传出去
          //binding.value({x:e.pageX,y:e.pageY})
        }
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
      dialogHeaderEl.onmousedown = moveDown;

      // 底部可以拖动 start
      const dialogFooterEl = el.querySelector('.el-dialog__footer');
      let moveDownFoot = (e) => {
        // 鼠标按下，计算当前元素距离可视区的距离
        const disX = e.clientX - dialogFooterEl.offsetLeft;
        const disY = e.clientY - dialogFooterEl.offsetTop;

        let  height = document.getElementsByClassName("summaryDialog")[0].getElementsByClassName('el-dialog')[0].offsetHeight 
        // console.log("99999小结height",height)
        const height2 = height -56

        // 获取到的值带px 正则匹配替换
        let styL, styT;
        // 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 (sty.left.includes('%')) {
          styL = +document.body.clientWidth * (+sty.left.replace(/%/g, '') / 100);
          styT = +document.body.clientHeight * (+sty.top.replace(/%/g, '') / 100);
        } else {
          styL = +sty.left.replace(/px/g, '');
          styT = +sty.top.replace(/px/g, '');
        }
        const bodyWidth = document.body.clientWidth
        const bodyHeight = document.body.clientHeight // 获取屏幕高度
        document.onmousemove = function (e) {
          // 通过事件委托，计算移动的距离 
          const l = e.clientX - disX;
          const t = e.clientY - disY;

          // 限制不让拖出屏幕 *****
          if(e.clientY<100 || e.clientY > bodyHeight -20){
            return 
          }
          if(e.clientX<100 || e.clientX > bodyWidth -100){
            return 
          }

          // 移动当前元素  
          dragDom.style.left = `${l + styL}px`;
          dragDom.style.top = `${t + styT -height2  }px`;
          //将此时的位置传出去
          //binding.value({x:e.pageX,y:e.pageY})
        }
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
      // dialogFooterEl.style.cursor = 'move';
      // dialogFooterEl.onmousedown = moveDownFoot;
      // 底部可以拖动 end


      //双击头部效果
      dialogHeaderEl.ondblclick = (e) => {
        if (isFullScreen == false) {
          nowHight = dragDom.clientHeight;
          nowWidth = dragDom.clientWidth;
          nowMarginTop = dragDom.style.marginTop;
          dragDom.style.left = 0;
          dragDom.style.top = 0;
          dragDom.style.height = "100VH";
          dragDom.style.width = "100VW";
          dragDom.style.marginTop = 0;
          isFullScreen = true;
          dialogHeaderEl.style.cursor = 'initial';
          dialogHeaderEl.onmousedown = null;
        } else {
          dragDom.style.height = "auto";
          dragDom.style.width = nowWidth + 'px';
          dragDom.style.marginTop = nowMarginTop;
          isFullScreen = false;
          dialogHeaderEl.style.cursor = 'move';
          dialogHeaderEl.onmousedown = moveDown;
        }
      }
      
      //拉伸(右下方)
      let resizeEl=document.createElement("div");
      dragDom.appendChild(resizeEl); 
      //在弹窗右下角加上一个10-10px的控制块
      resizeEl.style.cursor = 'se-resize';
      resizeEl.style.position = 'absolute';
      resizeEl.style.height = '10px';
      resizeEl.style.width = '10px';
      resizeEl.style.right = '0px';
      resizeEl.style.bottom = '0px';
      resizeEl.style.zIndex = '99';
      //鼠标拉伸弹窗
      resizeEl.onmousedown = (e) => {
        // 记录初始x位置
        let clientX = e.clientX;
        // 鼠标按下，计算当前元素距离可视区的距离
        let disX = e.clientX - resizeEl.offsetLeft;
        let disY = e.clientY - resizeEl.offsetTop;
        document.onmousemove = function (e) {
          e.preventDefault(); // 移动时禁用默认事件
          
          // 通过事件委托，计算移动的距离
          let x = e.clientX - disX + (e.clientX - clientX);//这里 由于elementUI的dialog控制居中的，所以水平拉伸效果是双倍
          let y = e.clientY - disY;
          //比较是否小于最小宽高
          dragDom.style.width = x > minWidth ? `${x}px` : minWidth + 'px';
          dragDom.style.height = y > minHeight ? `${y}px` : minHeight + 'px';
          };
        //拉伸结束
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }

      //拉伸(左下方)
      let resizeElLeft=document.createElement("div");
      dragDom.appendChild(resizeElLeft); 
      //在弹窗右下角加上一个10-10px的控制块
      resizeElLeft.style.cursor = 'sw-resize';
      resizeElLeft.style.position = 'absolute';
      resizeElLeft.style.height = '10px';
      resizeElLeft.style.width = '10px';
      resizeElLeft.style.left = '0px';
      resizeElLeft.style.bottom = '0px';
      resizeElLeft.style.zIndex = '99';
      //鼠标拉伸弹窗
      resizeElLeft.onmousedown = (e) => {
        // 记录初始x位置
        let clientX = e.clientX;
        // 鼠标按下，计算当前元素距离可视区的距离

        let disX = dragDom.clientWidth;  // 鼠标按下 记录元素的宽

        let disY = e.clientY - resizeElLeft.offsetTop;
        document.onmousemove = function (e) {
          e.preventDefault(); // 移动时禁用默认事件
          
          // 通过事件委托，计算移动的距离
          let x = disX + (clientX - e.clientX)*2;//这里 由于elementUI的dialog控制居中的，所以水平拉伸效果是双倍
          let y = e.clientY - disY;
          //比较是否小于最小宽高
          dragDom.style.width = x > minWidth ? `${x}px` : minWidth + 'px';
          dragDom.style.height = y > minHeight ? `${y}px` : minHeight + 'px';
          };
        //拉伸结束
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
      
      //拉伸(右边)
      let resizeElR=document.createElement("div");
      dragDom.appendChild(resizeElR); 
      //在弹窗右下角加上一个10-10px的控制块
      resizeElR.style.cursor = 'w-resize';
      resizeElR.style.position = 'absolute';
      resizeElR.style.height = '100%';
      resizeElR.style.width = '10px';
      resizeElR.style.right = '0px';
      resizeElR.style.top = '0px';
      //鼠标拉伸弹窗
      resizeElR.onmousedown = (e) => {
        let elW = dragDom.clientWidth;
        let EloffsetLeft = dragDom.offsetLeft;
        // 记录初始x位置
        let clientX = e.clientX;
        document.onmousemove = function (e) {
          e.preventDefault(); // 移动时禁用默认事件
          //右侧鼠标拖拽位置
          if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {
              //往左拖拽
              if (clientX > e.clientX) {
                  if (dragDom.clientWidth < minWidth) {
                    console.log(111)
                  } else {
                      dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px';
                  }
              }
              //往右拖拽
              if (clientX < e.clientX) {
                  dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px';
              }
          }
         
        };
        //拉伸结束
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
      
      //拉伸(左边)
      let resizeElL=document.createElement("div");
      dragDom.appendChild(resizeElL); 
      //在弹窗右下角加上一个10-10px的控制块
      resizeElL.style.cursor = 'w-resize';
      resizeElL.style.position = 'absolute';
      resizeElL.style.height = '100%';
      resizeElL.style.width = '10px';
      resizeElL.style.left = '0px';
      resizeElL.style.top = '0px';
      //鼠标拉伸弹窗
      resizeElL.onmousedown = (e) => {
        let elW = dragDom.clientWidth;
        let EloffsetLeft = dragDom.offsetLeft;
        // 记录初始x位置
        let clientX = e.clientX;
        document.onmousemove = function (e) {
          e.preventDefault(); // 移动时禁用默认事件
          //左侧鼠标拖拽位置
          if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
              //往左拖拽
              if (clientX > e.clientX) {
                  dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px';
              }
              //往右拖拽
              if (clientX < e.clientX) {
                  if (dragDom.clientWidth < minWidth) {
                    console.log(222)
                  } else {
                      dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px';
          
                  }
              }
          }
         
        };
        //拉伸结束
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
      
      // 拉伸(下边)
      let resizeElB=document.createElement("div");
      dragDom.appendChild(resizeElB); 
      //在弹窗右下角加上一个10-10px的控制块
      resizeElB.style.cursor = 'n-resize';
      resizeElB.style.position = 'absolute';
      resizeElB.style.height = '10px';
      resizeElB.style.width = '100%';
      resizeElB.style.left = '0px';
      resizeElB.style.bottom = '0px';
      //鼠标拉伸弹窗
      resizeElB.onmousedown = (e) => {
       let EloffsetTop = dragDom.offsetTop;
       let ELscrollTop = el.scrollTop;
        let clientY = e.clientY;
        let elH = dragDom.clientHeight;
        document.onmousemove = function (e) {
          e.preventDefault(); // 移动时禁用默认事件
          //底部鼠标拖拽位置
          if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {
              //往上拖拽
              if (clientY > e.clientY) {
                  if (dragDom.clientHeight < minHeight) {
                    console.log(333)
                  } else {
                      dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px';
                  }
              }
              //往下拖拽
              if (clientY < e.clientY) {
                  dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px';
              }
          }
        };
        //拉伸结束
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      }
    }
  })

【main.js】

import '@/utils/directives'; // 弹窗拖拽

【使用】

<el-dialog
    v-dialog-drag >

弹窗只带拖拽，不带缩放功能

// directives.js

import Vue from 'vue';
// v-dialogDrag: 弹窗拖拽
Vue.directive('dialogDrag', {
  bind: function(el, binding, vnode) {
    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 getStyle = (function() {
      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 dragDomWidth = dragDom.offsetWidth
      const dragDomheight = dragDom.offsetHeight

      const screenWidth = document.body.clientWidth
      const screenHeight = document.body.clientHeight

      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 = getStyle(dragDom, 'left')
      let styT = getStyle(dragDom, 'top')

      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;`

        // emit onDrag event
        vnode&&vnode.child.$emit('dragDialog')
      }

      document.onmouseup = function() {
        document.onmousemove = null
        document.onmouseup = null
      }
    }
  }
});