fix: FluentValidationMessage won't show message for an empty FluentTextArea component.

[MertYacan]

🐛 Bug Report

FluentValidationMessage doesn't show an error message for a fluent text area with required field set true.

💻 Repro or Code Sample

@page "/test"

<EditForm Model="@dto" OnValidSubmit="HandleValidSubmit" FormName="batchForm">
    <DataAnnotationsValidator />
    <FluentValidationSummary />

    <FluentStack Orientation="Orientation.Vertical">
        <div>
            <FluentTextArea Rows=5 Cols=60 Name="description" @bind-Value="dto.Description" Label="Description" Required="true" />
            <FluentValidationMessage For="@(() => dto.Description)" />  @* This won't show message *@
        </div>
        <div>
            From:
            <FluentDatePicker @bind-Value="@(dto.From)" Required />
            <FluentTimePicker @bind-Value="@(dto.From)" />
            <br />
        </div>
        <div>
            To:
            <FluentDatePicker @bind-Value="@(dto.To)" Required />
            <FluentTimePicker @bind-Value="@(dto.To)" />
            <br />
        </div>

        <FluentCheckbox @bind-Value="@(dto.IsAdministrative)" Disabled="true" Label="Administrative Leave" />
        <FluentButton Type="ButtonType.Submit" Appearance="Appearance.Accent" Disabled="@(processing)">Submit</FluentButton>
    </FluentStack>
</EditForm>

@code {
    [SupplyParameterFromForm]
    private CreateBatchLeaveExcelDto dto { get; set; } = new()
        {
            From = new DateTime(DateOnly.FromDateTime(DateTime.Now), new TimeOnly(8, 0)),
            To = new DateTime(DateOnly.FromDateTime(DateTime.Now), new TimeOnly(17, 0))
        };

    private bool processing = false;

    public class CreateBatchLeaveExcelDto
    {
        public DateTime? From { get; set; }
        public DateTime? To { get; set; }
        public string? Description { get; set; }
        public bool IsAdministrative { get; set; }
    }

    private async Task HandleValidSubmit()

    {
        processing = true;
        await Task.Delay(500);
        processing = false;
    }
}

🤔 Expected Behavior

Works with FluentTextField

😯 Current Behavior

Doesn't work with FluentTextArea

🌍 Your Environment

• OS & Device: Windows on PC
• Browser: Google Chrome
• .NET and Fluent UI Blazor library Version 4.7.2

[vnbaaij]

Hi,

Provided sample code is not ready-to-run. Please complement.

[MertYacan]

Hi,

I am sorry. It should be ready-to-run now.

I realized when I run the app, and click submit it won't show the error message.

If i write something inside the description and clear the description again, then it will start to show the error message.

Thank you.

[vnbaaij]

It seems the standard HTML 5 validation checking and the FluentTextArea are not playing together nicely. I'll need to look into that further.

In the meantime I would advise you to not use the standard HTML validation but use Blazor's icw ours. Here is what you need to do:

1. add @using System.ComponentModel.DataAnnotations at the top of your page
2. add novalidate to your EditForm tag
3. change your CreateBatchLeaveExcelDto class to have:

 [Required(ErrorMessage = "Description is required")]
 public string? Description { get; set; }

Then clicking submit will show you an error immediately(*)

Added benefit is that it will show the errors in the correct Fluent Design (as shown above) instead of the generic design (as shown below)

(which looks way worse if you ask ,e

(*) It will show the red border if below is in your CSS somewhere. I'm currently working on this and it will be automatically included in next release

fluent-text-area.invalid::part(control), 
fluent-text-field.invalid::part(root) {
    outline: calc(var(--stroke-width)* 1px) solid var(--error);
}

PS: Setting `Required="true" on a field does not automatically add any checks or logic. It's sole task (currently) is to display the required indicator (the red *)

[vnbaaij]

Closing this as a workaround is provided

[MertYacan]

Hi Vincent,

Thank you very much for the detailed explanation. It worked with your suggested changes.