Collect User Input

<EditForm Model="Employee" OnValidSubmit="HandleSubmit" FormName="employee">
    <DataAnnotationsValidator />
    <ValidationSummary />

    <label>
        Name: <InputText @bind-Value="Employee!.Name" />
        <ValidationMessage For="() => Employee!.Name" />
    </label>

    <button type="submit">Save</button>
</EditForm>

@code {
    [SupplyParameterFromForm]
    private EmployeeModel? Employee { get; set; }

    protected override void OnInitialized() => Employee ??= new();

    private async Task HandleSubmit()
    {
        // Save Employee
    }
}

private EditContext? editContext;
private EmployeeModel model = new();

protected override void OnInitialized()
{
    editContext = new EditContext(model);
}

<EditForm EditContext="editContext" OnValidSubmit="HandleSubmit" FormName="employee">

<InputSelect @bind-Value="Model!.Status">
    <option value="">-- Select --</option>
    @foreach (var value in Enum.GetValues<OrderStatus>())
    {
        <option value="@value">@value</option>
    }
</InputSelect>

<InputRadioGroup @bind-Value="Model!.Priority">
    @foreach (var p in Enum.GetValues<Priority>())
    {
        <label>
            <InputRadio Value="p" /> @p
        </label>
    }
</InputRadioGroup>

public class EmployeeModel
{
    [Required, StringLength(100)]
    public string? Name { get; set; }

    [Required, EmailAddress]
    public string? Email { get; set; }

    [Range(18, 99)]
    public int Age { get; set; }

    [Required]
    public string? Department { get; set; }
}

public class CustomValidator : ComponentBase
{
    [CascadingParameter]
    private EditContext? EditContext { get; set; }

    private ValidationMessageStore? messageStore;

    protected override void OnInitialized()
    {
        messageStore = new ValidationMessageStore(EditContext!);
        EditContext!.OnValidationRequested += (s, e) => messageStore.Clear();
        EditContext!.OnFieldChanged += (s, e) => messageStore.Clear(e.FieldIdentifier);
    }

    public void DisplayErrors(Dictionary<string, List<string>> errors)
    {
        foreach (var (field, messages) in errors)
        {
            foreach (var message in messages)
            {
                messageStore!.Add(EditContext!.Field(field), message);
            }
        }
        EditContext!.NotifyValidationStateChanged();
    }

    public void ClearErrors()
    {
        messageStore?.Clear();
        EditContext?.NotifyValidationStateChanged();
    }
}

<EditForm Model="Model" OnValidSubmit="HandleSubmit" FormName="register">
    <DataAnnotationsValidator />
    <CustomValidator @ref="customValidator" />
    <ValidationSummary />
    @* inputs *@
</EditForm>

@code {
    private CustomValidator? customValidator;

    private async Task HandleSubmit()
    {
        var errors = await RegistrationService.ValidateAsync(Model!);
        if (errors.Count > 0)
        {
            customValidator!.DisplayErrors(errors);
            return;
        }
        // proceed
    }
}

<InputText @bind-Value="Model!.ZipCode" @bind:after="OnZipCodeChanged" />

@code {
    private async Task OnZipCodeChanged()
    {
        // Fetch city/state based on new zip code
        var location = await LocationService.LookupAsync(Model!.ZipCode);
        Model.City = location?.City;
        Model.State = location?.State;
    }
}

<input type="text" @oninput="OnSearchInput" placeholder="Search..." />

@code {
    private string searchTerm = "";
    private List<Item> filteredItems = new();

    private void OnSearchInput(ChangeEventArgs e)
    {
        searchTerm = e.Value?.ToString() ?? "";
        filteredItems = allItems.Where(i =>
            i.Name.Contains(searchTerm, StringComparison.OrdinalIgnoreCase)).ToList();
    }
}

[SupplyParameterFromForm]
private ContactModel? Contact { get; set; }

protected override void OnInitialized() => Contact ??= new();