How to merge htmlAttributes into user helper

Question

I have a custom helper where I get the htmlAttributes parameter as a parameter:

public static MvcHtmlString Campo<TModel, TValue>( this HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression, dynamic htmlAttributes = null) { var attr = MergeAnonymous(new { @class = "form-control"}, htmlAttributes); var editor = helper.EditorFor(expression, new { htmlAttributes = attr }); ... } 

The MergeAnonymous method should return the combined htmlAttributes obtained in the parameter using "new {@ class =" form-control "}":

 static dynamic MergeAnonymous(dynamic obj1, dynamic obj2) { var dict1 = new RouteValueDictionary(obj1); if (obj2 != null) { var dict2 = new RouteValueDictionary(obj2); foreach (var pair in dict2) { dict1[pair.Key] = pair.Value; } } return dict1; } 

And in the Editor Template for the example field, I need to add a few more attributes:

 @model decimal? @{ var htmlAttributes = HtmlHelper.AnonymousObjectToHtmlAttributes(ViewData["htmlAttributes"]); htmlAttributes["class"] += " inputmask-decimal"; } @Html.TextBox("", string.Format("{0:c}", Model.ToString()), htmlAttributes) 

What I have in htmlAttributes in the last line in the editor template:

Click here to see the image.

Please note that the “class” is displayed correctly, but the rest of the attributes from the extension helper are contained in the dictionary, what am I doing wrong?

If possible, I want to change only the Extension Helper, not the Editor Template, so I think that the RouteValueDictionary passed to EditorFor needs to be sent to an anonymous object ...

Answer 1

I decided to change all my editor templates to a line:

 var htmlAttributes = HtmlHelper.AnonymousObjectToHtmlAttributes(ViewData["htmlAttributes"]); 

for this:

 var htmlAttributes = ViewData["htmlAttributes"] as IDictionary<string, object> ?? HtmlHelper.AnonymousObjectToHtmlAttributes(ViewData["htmlAttributes"]); 

and MergeAnonymous method:

 static IDictionary<string,object> MergeAnonymous(object obj1, object obj2) { var dict1 = new RouteValueDictionary(obj1); var dict2 = new RouteValueDictionary(obj2); IDictionary<string, object> result = new Dictionary<string, object>(); foreach (var pair in dict1.Concat(dict2)) { result.Add(pair); } return result; } 

Answer 2

 public static class CustomHelper { public static MvcHtmlString Custom(this HtmlHelper helper, string tagBuilder, object htmlAttributes) { var builder = new TagBuilder(tagBuilder); RouteValueDictionary customAttributes = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes); foreach (KeyValuePair<string, object> customAttribute in customAttributes) { builder.MergeAttribute(customAttribute.Key.ToString(), customAttribute.Value.ToString()); } return MvcHtmlString.Create(builder.ToString(TagRenderMode.SelfClosing)); } }