HTML and CSS Reference
In-Depth Information
string placeHolder;
string value;
string valueAttribute;
ViewDataDictionary viewData = htmlHelper.ViewData;
ModelMetadata metaData = viewData.ModelMetadata;
// Build the HTML attributes
id = viewData.TemplateInfo.GetFullHtmlFieldId(string.Empty);
name = viewData.TemplateInfo.GetFullHtmlFieldName(string.Empty);
if (string.IsNullOrWhiteSpace(metaData.Watermark))
placeHolder = string.Empty;
placeHolder = "placeholder=\"" + metaData.Watermark + "\"";
value = viewData.TemplateInfo.FormattedModelValue.ToString();
if (string.IsNullOrWhiteSpace(value))
valueAttribute = string.Empty;
valueAttribute = "value=\"" + value + "\"";
// Determine the css class
string css = "text-box single-line";
ModelState state;
if (viewData.ModelState.TryGetValue(name, out state)
&& (state.Errors.Count > 0))
css += " " + HtmlHelper.ValidationInputCssClassName;
// Format the final HTML
string markup = string.Format(Culture,
"<input type=\"email\" id=\"{0}\" name=\"{1}\" {2} {3} " +
"class=\"{4}\"/>", id, name, placeHolder, valueAttribute, css);
return MvcHtmlString.Create(markup);
This method gathers the various HTML attributes such as id , name , class , and placeholder . This
information is extracted from the model or the model metadata. At the end of this method, the markup string is
built using the standard string.Format() method, which assembles the various attributes. This is then passed to
the static MvcHtmlString.Create() method to provide this as the IHtmlString interface that the MVC framework
The primary difference in this implementation of the EmailAddress template is that the placeholder attribute
is set using the model metadata. The previous implementation used a hard-coded placeholder, “Enter an e-mail
address”. Unfortunately, the property names are completely inconsistent. In the model, this is specified using the
Prompt attribute ( Prompt = "Preferred e-mail address" ). In the ModelMetadata class, this value is provided as
the Watermark property. And, of course, this is included in the HTML document as a placeholder attribute.
Re-implementing the Custom Email Template
Now you'll replace the EmailAddress template with a much simpler one that uses the new helper extension that
you've just implemented.
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