How to get values out of object HtmlAttributes

Question

In asp.net mvc I always see the built in html helpers they always have object htmlAttirbutes.

Then I usually do new {@id = \"test\", @class=\"myClass\"}.

How do

Answer 1

I use a mix of both methods (Chtiwi Malek and rrejc) proposed earlier and it works great.

With this method, it will convert data_id to data-id. It will also overwrite default attribute values you have set earlier.

using System.ComponentModel;
...


public static MvcHtmlString RequiredLabelFor(this HtmlHelper helper, Expression> expression, object htmlAttributes)
{
    var metaData = ModelMetadata.FromLambdaExpression(expression, helper.ViewData);

    string htmlFieldName = ExpressionHelper.GetExpressionText(expression);
    string labelText = metaData.DisplayName ?? metaData.PropertyName ?? htmlFieldName.Split('.').Last();

    if (String.IsNullOrEmpty(labelText))
        return MvcHtmlString.Empty;

    var label = new TagBuilder("label");
    label.Attributes.Add("for", helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldId(htmlFieldName));

    foreach (PropertyDescriptor prop in TypeDescriptor.GetProperties(htmlAttributes))
    {
        // By adding the 'true' as the third parameter, you can overwrite whatever default attribute you have set earlier.
        label.MergeAttribute(prop.Name.Replace('_', '-'), prop.GetValue(htmlAttributes).ToString(), true);
    }
    label.InnerHtml = labelText;
    return MvcHtmlString.Create(label.ToString());
}

Note the comment about overwriting an attribute that has a default value in your code in the foreach.