Filtering in EJ2 JavaScript Drop down list control
22 Jun 202419 minutes to read
The DropDownList has built-in support to filter data items when allowFiltering is enabled. The filter
operation starts as soon as you start typing characters in the search box.
To display filtered items in the popup, filter the required data and return it to the DropDownList via updateData method by using the filtering event.
The following sample illustrates how to query the data source and pass the data to the DropDownList through the updateData method in filtering event.
//initiates the component
var ddlObject = new ej.dropdowns.DropDownList({
//bind the data manager instance to dataSource property
dataSource: new ej.data.DataManager({
url: 'https://services.odata.org/V4/Northwind/Northwind.svc/Customers',
adaptor: new ej.data.ODataV4Adaptor(),
crossDomain: true
}),
//bind the Query instance to query property
query: new ej.data.Query().select(['ContactName']),
//map the appropriate columns to fields property
fields: { value: 'ContactName'},
//set the placeholder to DropDownList input
placeholder: "Find a customer",
//set the filterType to searching operation
filterType: 'StartsWith',
//sort the resulted items
sortOrder: 'Ascending'
});
//render the component
ddlObject.appendTo('#ddlelement');<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 DropDownList</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript UI Controls">
<meta name="author" content="Syncfusion">
<link href="styles.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/27.2.2/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container" style="margin:0 auto; width:250px;">
<br>
<input type="text" id="ddlelement">
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Limit the minimum filter character
When filtering the list items, you can set the limit for character count to raise remote request and fetch filtered data on the DropDownList. This can be done by manual validation within the filter event handler.
In the following example, the remote request does not fetch the search data until the search key contains three characters.
//initiates the component
var searchData = new ej.data.DataManager({
url: 'https://services.odata.org/V4/Northwind/Northwind.svc/Customers',
adaptor: new ej.data.ODataV4Adaptor(),
crossDomain: true
});
var ddlObject = new ej.dropdowns.DropDownList({
dataSource: searchData,
query: new ej.data.Query().select(['ContactName', 'CustomerID']).take(7),
// map the appropriate column
fields: { text: 'ContactName', value: 'CustomerID' },
// set placeholder to DropDownList input element
placeholder:"Select customers",
//sort the resulted items
sortOrder: 'Ascending',
// set true to allowFiltering for enable filtering supports
allowFiltering: true,
//bind the filtering event handler
filtering: (e) => {
// load overall data when search key empty.
if(e.text == '') e.updateData(searchData);
else{
// restrict the remote request until search key contains 3 characters.
if (e.text.length < 3) { return; }
var query = new ej.data.Query().select(['ContactName', 'CustomerID']);
query = (e.text !== '') ? query.where('ContactName', 'startswith', e.text, true) : query;
e.updateData(searchData, query);
}
}
});
//render the component
ddlObject.appendTo('#ddlelement');<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 DropDownList</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript UI Controls">
<meta name="author" content="Syncfusion">
<link href="styles.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/27.2.2/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container" style="margin:0 auto; width:250px;">
<br>
<input type="text" id="ddlelement">
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Change the filter type
While filtering, you can change the filter type to contains, startsWith, or endsWith for string type within the filter event handler.
In the following examples, data filtering is done with endsWith type.
//initiates the component
var searchData = new ej.data.DataManager({
url: 'https://services.odata.org/V4/Northwind/Northwind.svc/Customers',
adaptor: new ej.data.ODataV4Adaptor(),
crossDomain: true
});
var ddlObject = new ej.dropdowns.DropDownList({
dataSource: searchData,
query: new ej.data.Query().select(['ContactName', 'CustomerID']).take(7),
// map the appropriate column
fields: { text: 'ContactName', value: 'CustomerID' },
// set placeholder to DropDownList input element
placeholder:"Select customers",
//sort the resulted items
sortOrder: 'Ascending',
// set true to allowFiltering for enable filtering supports
allowFiltering: true,
//bind the filtering event handler
filtering: (e) => {
// load overall data when search key empty.
if(e.text == '') e.updateData(searchData);
else{
var query = new ej.data.Query().select(['ContactName', 'CustomerID']);
query = (e.text !== '') ? query.where('ContactName', 'startswith', e.text, true) : query;
e.updateData(searchData, query);
}
}
});
//render the component
ddlObject.appendTo('#ddlelement');<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 DropDownList</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript UI Controls">
<meta name="author" content="Syncfusion">
<link href="styles.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/27.2.2/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container" style="margin:0 auto; width:250px;">
<br>
<input type="text" id="ddlelement">
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Case sensitive filtering
Data items can be filtered either with or without case sensitivity using the DataManager. This can be done by passing the fourth optional parameter of the where clause.
The following example shows how to perform case-sensitive filter.
//initiates the component
var searchData = new ej.data.DataManager({
url: 'https://services.odata.org/V4/Northwind/Northwind.svc/Customers',
adaptor: new ej.data.ODataV4Adaptor(),
crossDomain: true
});
var ddlObject = new ej.dropdowns.DropDownList({
dataSource: searchData,
query: new ej.data.Query().select(['ContactName', 'CustomerID']).take(7),
// map the appropriate column
fields: { text: 'ContactName', value: 'CustomerID' },
// set placeholder to DropDownList input element
placeholder:"Select customers",
//sort the resulted items
sortOrder: 'Ascending',
// set true to allowFiltering for enable filtering supports
allowFiltering: true,
//bind the filtering event handler
filtering: (e) => {
// load overall data when search key empty.
if(e.text == '') e.updateData(searchData);
else{
var query = new ej.data.Query().select(['ContactName', 'CustomerID']);
query = (e.text !== '') ? query.where('ContactName', 'startswith', e.text, true) : query;
e.updateData(searchData, query);
}
}
});
//render the component
ddlObject.appendTo('#ddlelement');<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 DropDownList</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript UI Controls">
<meta name="author" content="Syncfusion">
<link href="styles.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/27.2.2/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container" style="margin:0 auto; width:250px;">
<br>
<input type="text" id="ddlelement">
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>Diacritics Filtering
The DropDownList supports diacritics filtering which will ignore the diacritics and makes it easier to filter the results in international characters lists when the ignoreAccent is enabled.
In the following sample,data with diacritics are bound as dataSource for DropDownList.
// create local data
var data = [
'Aeróbics',
'Aeróbics en Agua',
'Aerografía',
'Aeromodelaje',
'Águilas',
'Ajedrez',
'Ala Delta',
'Álbumes de Música',
'Alusivos',
'Análisis de Escritura a Mano'];
// initialize DropDownList component
var ddlObj = new ej.dropdowns.DropDownList({
//set the local data to dataSource property
dataSource: data,
// set the placeholder to DropDownList input element
placeholder: 'Select a value',
// enabled the ignoreAccent property for ignore the diacritics
ignoreAccent: true,
// set true for enable the filtering support.
allowFiltering: true,
filterBarPlaceholder: 'e.g: aero'
});
ddlObj.appendTo('#ddlelement');<!DOCTYPE html><html lang="en"><head>
<title>Essential JS 2 DropDownList</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="Typescript UI Controls">
<meta name="author" content="Syncfusion">
<link href="styles.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-base/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-inputs/styles/material.css" rel="stylesheet">
<link href="https://cdn.syncfusion.com/ej2/27.2.2/ej2-dropdowns/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/27.2.2/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
<div id="container" style="margin:0 auto; width:250px;">
<br>
<input type="text" id="ddlelement">
</div>
<script>
var ele = document.getElementById('container');
if(ele) {
ele.style.visibility = "visible";
}
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>