New to Telerik UI for Blazor? Download free 30-day trial

Tooltip Does Not Update Content with the View-Model fields and events

Environment

Product Tooltip for Blazor

Description

When I have some dynamic content inside the tooltip template, the tooltip seems not to be re-rendering. E.g. when I have a tooltip with a text input and button and wish to disable the button when no text is entered, the tooltip seems to be only refreshing after closing and re-opening it. Calling StateHasChanged in the desired event does not help.

Steps to Reproduce

A simplified example - show the tooltip, type in the textbox - the expected behavior is that the button will get enabled, but it does not

@* Type in the textbox *@

<TelerikButton Class="search-tooltip" Primary="true">Click for tooltip</TelerikButton>

<TelerikTooltip TargetSelector=".search-tooltip" Position="TooltipPosition.Bottom" ShowOn="TooltipShowEvent.Click">
    <Template>
        <TelerikTextBox @bind-Value="@SearchText"></TelerikTextBox>
        <TelerikButton OnClick="@Search" Enabled="@(!string.IsNullOrEmpty(SearchText))">Search</TelerikButton>
    </Template>
</TelerikTooltip>

@code{
    string SearchText { get; set; }
    void Search()
    {
        Console.WriteLine("Search Click");
    }
}

Cause\Possible Cause(s)

The Tooltip component renders at the root of the app to ensure its correct position - it is a direct child of the <TelerikRootComponent> in the main layout.

This means that its content is no longer a sibling or child of the current component whose view-model you changed, and this is why calls to StateHasChanged do not update it.

Solution

The solution is to encapsulate the desired content in its own component so that its own logic and view-model updates itself and its own rendering, and changes from the parent component also fire up its OnParametersSet method so it can also re-render as needed.

You can expose the necessary parameters and events from it so that there are no API changes in the view-model of the main component

@* The API is the same, the contents are in their own component, see the adjacent tab *@

<TelerikButton Class="search-tooltip" Primary="true">Click for tooltip</TelerikButton>

<TelerikTooltip TargetSelector=".search-tooltip" Position="TooltipPosition.Bottom" ShowOn="TooltipShowEvent.Click">
    <Template>
        <SearchTooltipContent @bind-SearchText="@SearchText" OnSearch="@Search" />
    </Template>
</TelerikTooltip>

@code{
    string SearchText { get; set; }
    void Search()
    {
        Console.WriteLine("Search Click");
    }
}
@* Sample content for the tooltip that fires up the necessary events and can update as necessary *@

<TelerikTextBox Value="@SearchText" ValueChanged="@( (string v) => ValueChangedHandler(v) )"></TelerikTextBox>
<TelerikButton OnClick="@Search" Enabled="@(!string.IsNullOrEmpty(SearchText))">Search</TelerikButton>

@code {
    [Parameter]
    public string SearchText { get; set; }

    [Parameter]
    public EventCallback<string> SearchTextChanged { get; set; }

    [Parameter]
    public EventCallback OnSearch { get; set; }

    void ValueChangedHandler(string v)
    {
        SearchText = v;
        if (SearchTextChanged.HasDelegate)
        {
            SearchTextChanged.InvokeAsync(SearchText);
        }
    }

    async Task Search()
    {
        if (OnSearch.HasDelegate)
        {
            await OnSearch.InvokeAsync(null);
        }
    }
}
In this article
Not finding the help you need? Improve this article