您可以使用我们的过滤事件来实现自定义过滤功能的要求。

<ejs-multiselect id="list" placeholder="Select countries" query="@query" dataSource="@data"
                        allowFiltering="true" filtering="onFiltering">
            <e-multiselect-fields text="Name" value="Code"></e-multiselect-fields>
        </ejs-multiselect>

        <script type="text/javascript">
    function onFiltering(e) {
        var query = new ej.data.Query();
        // frame the query based on search string with filter type.
        query = (e.text !== '') ? query.where('Name', 'startswith', e.text, true) : query;
        // pass the filter data source, filter query to updateData method.
        e.updateData(@Html.Raw(JsonConvert.SerializeObject(data)), query);
    }
</script>

要了解有关自定义过滤的更多信息，请参阅以下文档和在线演示示例。在线演示示例：https://ej2.syncfusion.com/aspnetcore/MultiSelect/Filtering#/fluent文档链接：https://ej2.syncfusion.com/aspnetcore/documentation/multi-select/filtering