Setting the Operators

The Filter provides options for defining which filter operators will be displayed in the filtering drop-down.

Set operator per type

The operators field takes a literal with the available operators for each field type and you can list the desired operators together with their text.

The following example demonstrates how to set the equals and contains filter operators to the string fields and the greater than and less than filter operators to the numerical fields.

<div id="filter"></div>
<ul id="listView"></ul>

<script type="text/x-kendo-template" id="item">
    <li>
        <strong>#= name #</strong>, aged #= age #, is on vacation: #= isOnLeave #
    </li>
</script>

<script>
    $(document).ready(function () {
        var dataSource = new kendo.data.DataSource({
            data: [
                { name: "Jane Doe", age: "25", isOnLeave: false },
                { name: "John Doe", age: "33", isOnLeave: true },
                { name: "John Smith", age: "37", isOnLeave: true },
                { name: "Nathan Doe", age: 42, isOnLeave: false }
            ],
            schema: {
                model: {
                    fields: {
                        name: { type: "string" },
                        age: { type: "number" },
                        isOnLeave: { type: "boolean" }
                    }
                }
            }
        });

        $("#filter").kendoFilter({
            dataSource: dataSource,

            operators: {
                string: {
                    eq: kendo.ui.Filter.fn.options.operators.string.eq, // Take the default Kendo UI text.
                    contains: "Partially Matches" // Define a custom text.
                },
                number: {
                    gte: "Larger Than", // Define a custom text.
                    lt: kendo.ui.Filter.fn.options.operators.number.lt // Take the default Kendo UI text.
                }
            },

            expressionPreview: true, // Shows a text preview of the filter expression.
            applyButton: true, // Shows the built-in Apply button.
            fields: [ // Defining the fields is not mandatory. Otherwise, they will be taken from the data source schema.
                // If you define the fields, their names and types must match the data source definition.
                { name: "name", type: "string", label: "Name" },
                { name: "age", type: "number", label: "Age" },
                { name: "isOnLeave", type: "boolean", label: "On Vacation" }
            ],
            expression: { // Defining an initial filter expression is not required.
                logic: "and",
                filters: [
                    { field: "age", value: 30, operator: "gte" },
                    { field: "name", value: "Doe", operator: "contains" }
                ]
            }
        }).data("kendoFilter").applyFilter();
        // Chain the method call to immediately apply filtering after the widget initialization because an initial filter is set.

        $("#listView").kendoListView({
            dataSource: dataSource,
            template: kendo.template($("#item").html())
        });
    });
</script>

Set operator per field

The fields.operators configuration allows you to specify the available operators for the current field of the model.

The following example demonstrates how to set the equals and contains filter operators of the name field.

<div id="filter"></div>
<ul id="listView"></ul>

<script type="text/x-kendo-template" id="item">
    <li>
        <strong>#= name #</strong>, aged #= age #, is on vacation: #= isOnLeave #
    </li>
</script>

<script>
    $(document).ready(function () {
        var dataSource = new kendo.data.DataSource({
            data: [
                { name: "Jane Doe", age: "25", isOnLeave: false },
                { name: "John Doe", age: "33", isOnLeave: true },
                { name: "John Smith", age: "37", isOnLeave: true },
                { name: "Nathan Doe", age: 42, isOnLeave: false }
            ],
            schema: {
                model: {
                    fields: {
                        name: { type: "string" },
                        age: { type: "number" },
                        isOnLeave: { type: "boolean" }
                    }
                }
            }
        });

        $("#filter").kendoFilter({
            dataSource: dataSource,
            expressionPreview: true, // Shows a text preview of the filter expression.
            applyButton: true, // Shows the built-in Apply button.
            fields: [ // Defining the fields is not mandatory. Otherwise, they will be taken from the data source schema.
                // If you define the fields, their names and types must match the data source definition.
                { name: "name", type: "string", label: "Name", operators: {
                    string: {
                        eq: kendo.ui.Filter.fn.options.operators.string.eq, // Take the default Kendo UI text.
                        contains: "Partially Matches" // Define a custom text.
                    }
                } },
                { name: "age", type: "number", label: "Age" },
                { name: "isOnLeave", type: "boolean", label: "On Vacation" }
            ],
            expression: { // Defining an initial filter expression is not required.
                logic: "and",
                filters: [
                    { field: "age", value: 30, operator: "gte" },
                    { field: "name", value: "Doe", operator: "contains" }
                ]
            }
        }).data("kendoFilter").applyFilter();
        // Chain the method call to immediately apply filtering after the widget initialization because an initial filter is set.

        $("#listView").kendoListView({
            dataSource: dataSource,
            template: kendo.template($("#item").html())
        });
    });
</script>

Use custom operators

The operators.{type}.custom settings allows you to create a custom operator.

The following example demonstrates how to create a custom operator for string fields.

<div id="filter"></div>
<ul id="listView"></ul>

<script type="text/x-kendo-template" id="item">
    <li>
        <strong>#= name #</strong>, aged #= age #, is on vacation: #= isOnLeave #
    </li>
</script>

<script>
    $(document).ready(function () {
        var dataSource = new kendo.data.DataSource({
            data: [
                { name: "Jane Doe", age: "25", isOnLeave: false },
                { name: "John Doe", age: "33", isOnLeave: true },
                { name: "John Smith", age: "37", isOnLeave: true },
                { name: "Nathan Doe", age: 42, isOnLeave: false }
            ],
            schema: {
                model: {
                    fields: {
                        name: { type: "string" },
                        age: { type: "number" },
                        isOnLeave: { type: "boolean" }
                    }
                }
            }
        });

        $("#filter").kendoFilter({
            dataSource: dataSource,

            operators: {
                string: {
                    eq: kendo.ui.Filter.fn.options.operators.string.eq, // Take the default Kendo UI text.
                    contains: "Partially Matches", // Define a custom text.
                    myOperator: {
                        text: "Custom Operator",
                        handler: function(itemValue, filterValue){
                            return itemValue.indexOf(filterValue) > 2;
                        }
                    }
                },
                number: {
                    gte: "Larger Than", // Define a custom text.
                    lt: kendo.ui.Filter.fn.options.operators.number.lt // Take the default Kendo UI text.
                }
            },

            expressionPreview: true, // Shows a text preview of the filter expression.
            applyButton: true, // Shows the built-in Apply button.
            fields: [ // Defining the fields is not mandatory. Otherwise, they will be taken from the data source schema.
                // If you define the fields, their names and types must match the data source definition.
                { name: "name", type: "string", label: "Name" },
                { name: "age", type: "number", label: "Age" },
                { name: "isOnLeave", type: "boolean", label: "On Vacation" }
            ],
            expression: { // Defining an initial filter expression is not required.
                logic: "and",
                filters: [
                    { field: "age", value: 30, operator: "gte" },
                    { field: "name", value: "Doe", operator: "contains" }
                ]
            }
        }).data("kendoFilter").applyFilter();
        // Chain the method call to immediately apply filtering after the widget initialization because an initial filter is set.

        $("#listView").kendoListView({
            dataSource: dataSource,
            template: kendo.template($("#item").html())
        });
    });
</script>

See Also

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