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Grid Expand Button Tooltip


Product Grid for Blazor


Is there a tooltip option to add for the expend plus button on the left of a telerik grid row?

I want to add a tooltip to the hierarchy expand button for the detail template as an extra visual queue for my users.


You can use JS Interop to add title attributes on the grid elements.

You can call this JS function after the grid re-renders with new data by using its OnRead event.

The example below shows one way to do that, and to distinguish a particular grid, and to pass the title attribute value from the C# code so you can, for example, localize it.

@using Telerik.DataSource.Extensions
@inject IJSRuntime _js

<script suppress-error="BL9992">
    // move this script to a proper place in your project. 
    // the suppress-error hack is here to make it easy to copy-paste so you can run and test it
    function setGridExpandButtonTitles(gridSelector, tooltipText) {
        setTimeout(function () { // small timeout to have this run after the blazor render
            if (gridSelector) {
                // this selector targets all icons, you can extend it to distinguish between plus and minus icons if you want
                let expandButtons = document.querySelectorAll(gridSelector + " .k-hierarchy-cell > span.k-icon");
                expandButtons.forEach(elem => elem.setAttribute("title", tooltipText))
        }, 50);

<TelerikGrid TItem="@MainModel"
             Sortable="true" Pageable="true"
            var employee = context as MainModel;
            <TelerikGrid Data="employee.Orders" Pageable="true" PageSize="5">
                    <GridColumn Field="OrderId"></GridColumn>
                    <GridColumn Field="DealSize"></GridColumn>
        <GridColumn Field="Id"></GridColumn>
        <GridColumn Field="Name"></GridColumn>

@code {
    List<MainModel> AllData { get; set; }

    protected async Task ReadItems(GridReadEventArgs args)
        // typical data retrieval through OnRead
        var datasourceResult = AllData.ToDataSourceResult(args.Request);

        args.Data = datasourceResult.Data;
        args.Total = datasourceResult.Total;
        // end data operations

            // using try-catch to prevent JSInterop calls at too early stage
            // ensure the hierarchy expand icons have the desired tooltip after the grid re-renderes with new data
            await _js.InvokeVoidAsync("setGridExpandButtonTitles", ".titles-on-expand-buttons", "Expand Details");
        catch (InvalidOperationException e) { }

    // only data generation follows

    protected override void OnInitialized()
        AllData = GenerateData();

    private List<MainModel> GenerateData()
        List<MainModel> data = new List<MainModel>();
        for (int i = 0; i < 35; i++)
            MainModel mdl = new MainModel { Id = i, Name = $"Name {i}" };
            mdl.Orders = Enumerable.Range(1, 15).Select(x => new DetailsModel { OrderId = x, DealSize = x ^ i }).ToList();
        return data;

    public class MainModel
        public int Id { get; set; }
        public string Name { get; set; }
        public List<DetailsModel> Orders { get; set; }

    public class DetailsModel
        public int OrderId { get; set; }
        public double DealSize { get; set; }


If the detail template content is rather simple, you can consider dropping it in favor of tooltips for a particular item in the grid - text, a button, an icon - and load the content there so you don't have to have an extra column in the grid. You can find an example of adding tooltips to the grid here:

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