$(function(){
var MILLISECONDS_IN_DAY = 1000 * 60 * 60 * 24,
dataGrid;
$("#grid-container").dxDataGrid({
dataSource: {
store: {
type: "odata",
url: "https://js.devexpress.com/Demos/DevAV/odata/Tasks",
key: "Task_ID"
},
expand: "ResponsibleEmployee",
select: [
"Task_ID",
"Task_Subject",
"Task_Start_Date",
"Task_Due_Date",
"Task_Status",
"ResponsibleEmployee/Employee_Full_Name"
]
},
selection: {
mode: "multiple",
deferred: true
},
filterRow: {
visible: true
},
onInitialized: function (e) {
dataGrid = e.component;
calculateStatistics();
},
selectionFilter: ["Task_Status", "=", "Completed"],
showBorders: true,
columns: [{
caption: "Subject",
dataField: "Task_Subject"
}, {
caption: "Start Date",
dataField: "Task_Start_Date",
width: "auto",
dataType: "date"
}, {
caption: "Due Date",
dataField: "Task_Due_Date",
width: "auto",
dataType: "date"
}, {
caption: "Assigned To",
dataField: "ResponsibleEmployee.Employee_Full_Name",
width: "auto",
allowSorting: false
}, {
caption: "Status",
width: "auto",
dataField: "Task_Status"
}]
}).dxDataGrid("instance");
function calculateStatistics() {
dataGrid.getSelectedRowsData().then(function (rowData) {
var commonDuration = 0;
for (var i = 0; i < rowData.length; i++) {
commonDuration += rowData[i].Task_Due_Date - rowData[i].Task_Start_Date;
}
commonDuration = commonDuration / MILLISECONDS_IN_DAY;
$("#tasks-count").text(rowData.length);
$("#people-count").text(
DevExpress.data.query(rowData)
.groupBy("ResponsibleEmployee.Employee_Full_Name")
.toArray()
.length
);
$("#avg-duration").text(Math.round(commonDuration / rowData.length) || 0);
});
}
$("#calculateButton").dxButton({
text: "Get statistics on the selected tasks",
type: "default",
onClick: calculateStatistics
});
});
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>window.jQuery || document.write(decodeURIComponent('%3Cscript src="js/jquery.min.js"%3E%3C/script%3E'))</script>
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.4/css/dx.common.css" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/20.2.4/css/dx.light.css" />
<script src="https://cdn3.devexpress.com/jslib/20.2.4/js/dx.all.js"></script>
<link rel="stylesheet" type="text/css" href="styles.css" />
<script src="index.js"></script>
</head>
<body class="dx-viewport">
<div class="demo-container">
<div id="grid-container"></div>
<div class="selection-summary center">
<div id="calculateButton"></div>
<div>
<div class="column">
<span class="text count">Task count:</span>
<span class="value" id="tasks-count">0</span>
</div>
<div class="column">
<span class="text people-count">People assingned:</span>
<span class="value" id="people-count">0</span>
</div>
<div class="column">
<span class="text avg-duration">
Average task duration (days):
</span>
<span class="value" id="avg-duration">0</span>
</div>
</div>
</div>
</div>
</body>
</html>
#grid-container {
height: 400px;
}
.center {
text-align: center;
}
.selection-summary {
border: 1px solid rgba(161, 161,161, 0.2);
padding: 25px;
}
.column {
margin: 20px 30px 0 0;
display: inline-block;
white-space: nowrap;
text-align: right;
}
.value {
font-size: 40px;
display: inline-block;
vertical-align: middle;
}
.text {
text-align: left;
white-space: normal;
display: inline-block;
vertical-align: middle;
}
.avg-duration {
width: 100px;
}
.count{
width: 40px;
}
.people-count {
width: 65px;
}
