maxlength attribute of a text box from the DataAnnotations StringLength in Asp.Net MVC

Question

I am working on an MVC2 application and want to set the maxlength attributes of the text inputs.

I have already defined the stringlength attribute on the Model objec

Answer 1

I am not aware of any way to achieve this without resorting to reflection. You could write a helper method:

public static MvcHtmlString CustomTextBoxFor(
    this HtmlHelper htmlHelper, 
    Expression> expression, 
    object htmlAttributes
)
{
    var member = expression.Body as MemberExpression;
    var stringLength = member.Member
        .GetCustomAttributes(typeof(StringLengthAttribute), false)
        .FirstOrDefault() as StringLengthAttribute;

    var attributes = (IDictionary)new RouteValueDictionary(htmlAttributes);
    if (stringLength != null)
    {
        attributes.Add("maxlength", stringLength.MaximumLength);
    }
    return htmlHelper.TextBoxFor(expression, attributes);
}

which you could use like this:

<%= Html.CustomTextBoxFor(model => model.Address1, new { @class = "text long" })%>