Question

I can’t use EditorFor because my inputs have some other attributes like readonly, disable and class therefor i am using an extension for TextBoxFor. I need to display formatted numeric value so my extension method is defined as

public static MvcHtmlString FieldForAmount<TModel, TValue>(
    this HtmlHelper<TModel> htmlHelper, 
    Expression<Func<TModel, TValue>> expression)
{
    MvcHtmlString html = default(MvcHtmlString);
    Dictionary<string, object> newHtmlAttrib = new Dictionary<string, object>();

    newHtmlAttrib.Add("readonly", "readonly");
    newHtmlAttrib.Add("class", "lockedField amountField");

    var _value = ModelMetadata.FromLambdaExpression(expression, 
                     htmlHelper.ViewData).Model;
    newHtmlAttrib.Add("value", string.Format(Formats.AmountFormat, value));

    html = System.Web.Mvc.Html.InputExtensions.TextBoxFor(htmlHelper, 
        expression, newHtmlAttrib);
    return html;
}

Formats.AmountFormat is defined as "{0:#,##0.00##########}".

Lets say _value is 2, newHtmlAttrib shows it as 2.00 but the resultant html shows 0, it always shows 0 regardless of any value.
Where am i wrong or what can i do to get it fixed?

Answer 1

You should use the TextBox helper if you want to specify a format:

public static MvcHtmlString FieldForAmount<TModel, TValue>(
    this HtmlHelper<TModel> htmlHelper,
    Expression<Func<TModel, TValue>> expression
)
{
    var htmlAttributes = new Dictionary<string, object>
    {
        { "readonly", "readonly" },
        { "class", "lockedField amountField" },
    };

    var metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
    var value = string.Format(Formats.AmountFormat, metadata.Model);
    var name = ExpressionHelper.GetExpressionText(expression);
    var fullHtmlFieldName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);

    return htmlHelper.TextBox(fullHtmlFieldName, value, htmlAttributes);
}