项目场景：
echarts折线图需要根据条件动态展示多条不同曲线
解决方案：
后端直接将使用sql将数据查询出来返回即可,因为我这里不是Java使用的C#不是很熟练后台不好写逻辑,所以在前端js完成的
代码如下:
function createline(villagename, buildingname, unitname, roomname, startime, stoptime) {// console.log("roomname: "+roomname)//$("#demo").empty();var myChart = echarts.init(document.getElementById('demo'), myEchartsTheme);myChart.clear();var tempindoor = [],tempset = [],tempwaterin = [],tempwaterout = [];$.ajax({type: 'post',url: '../AJAXHandler.ashx',data: {"Method": "GetData","limit": 99999,"page": 1,"VillageName": villagename,"BuildingName": buildingname,"UnitName": unitname,"RoomName": roomname,"startime": startime,"stoptime": stoptime},success: function (res) {var xData = [];//console.log("res: "+res);var json = $.parseJSON(res);json = json.data;for (var i = 0; i < json.length; i++) {tempindoor.push(json[i].TMP_INDOOR);//console.log("tempindoor: "+tempindoor);tempset.push(json[i].TMP_SET);tempwaterin.push(json[i].TEMP_WATER_IN);tempwaterout.push(json[i].TEMP_WATER_OUT);xData.push(new Date(json[i].RTime).format('yyyy-MM-dd hh:mm:ss'));}
/**这里定义新的数组将查到的数据通过遍历存到新数组内,然后根据判断是否有相同的数据,如果没有就走if内的语句存入数组内,如果有相同的就走else内的语句,之后将数据存到map里根据条件去展示符合的数据,然后将这个map存到echarts渲染的部分的数组内 就可以做到动态展示了**/const result = [];json.forEach((item) => {const index = result.findIndex((r) => r.room === item.room);if (index === -1) {result.push({ room: item.room, names: [item.TMP_INDOOR] });} else {result[index].names.push(item.TMP_INDOOR);}});//console.log(result);const legend = result.map(item => item.room); // 图例const arr = result.map(item => ({ // 数据name: item.room,type: "line",data: item.names}));//手机适配if (window.screen.width < 1000) {var legends = {x: '100px',//data: ['室内温度', '设定温度', '进水温度', '回水温度']data: ['室内温度'],textStyle: {color: '#009688'}};} else {var legends = {x: 'center',//data: ['室内温度', '设定温度', '进水温度', '回水温度']data: ['室内温度'],textStyle: {color: '#009688'}};}var option = createoption('单位:℃', xData, legends, arr);myChart.setOption(option, true);//EChars图手机适配window.onresize = myChart.resize;},error: function () {//alert("折线图报错!");}});tempindoor = [], tempset = [], tempwaterin = [], tempwaterout = [];}
