Blazor provides a powerful EditForm component for building forms with built-in validation using DataAnnotations.

The Model

public class LoginModel
{
    [Required]
    public string Username { get; set; } = "";

    [Required, MinLength(8)]
    public string Password { get; set; } = "";
}

The Form

<EditForm Model="loginModel" OnValidSubmit="HandleLogin">
    <DataAnnotationsValidator />
    <ValidationSummary />

    <InputText @bind-Value="loginModel.Username" />
    <ValidationMessage For="() => loginModel.Username" />

    <button type="submit">Log In</button>
</EditForm>

@code {
    private LoginModel loginModel = new();
    private async Task HandleLogin() { /* only called when valid */ }
}

Built-in Input Components

• InputText — text input
• InputNumber — numeric input
• InputDate — date picker
• InputCheckbox — checkbox
• InputSelect — dropdown
• InputTextArea — multiline text

Reference:

Wikipedia: HTML Form

https://en.wikipedia.org/wiki/Form_(HTML)