Question

I have a curious problem with ASP.NET MVC3 client-side validation. I have the following class:

public class Instrument : BaseObject
{
    public int Id { get; set; }

    [Required(ErrorMessage = "Name is required.")]
    [MaxLength(40, ErrorMessage = "Name cannot be longer than 40 characters.")]
    public string Name { get; set; }
}

From my view:

<div class="editor-field">
    @Html.EditorFor(model => model.Name)
    @Html.ValidationMessageFor(model => model.Name)
</div>

And here’s the generated HTML I get for the textbox for this field:

<input class="text-box single-line" data-val="true" data-val-required="Name is required." id="Name" name="Name" type="text" value="">

No sign of the MaxLengthAttribute, but everything else seems to be working.

Any ideas what’s going wrong?

Answer 1

Try using the [StringLength] attribute:

[Required(ErrorMessage = "Name is required.")]
[StringLength(40, ErrorMessage = "Name cannot be longer than 40 characters.")]
public string Name { get; set; }

That’s for validation purposes. If you want to set for example the maxlength attribute on the input you could write a custom data annotations metadata provider as shown in this post and customize the default templates.