How to write custom ASP.NET MVC HTML Helper like Html.TextBoxFor and set correct name attribute

Question

I want to have custom Html.DateTimePickerFor(a => a.Fields[0].Id, value)

so the result should be like this:

<div name="Fields[0].Id"></div>

Currently I use Html.DatetimePicker("Fields[0].Id", value) and it works perfectly, but I wan to generate dynamic name.

So the question is how to set correct "name" attribute?

Answer 1

Try this. It works for me.

    public static MvcHtmlString DateTimePickerFor<TModel, TProp>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProp>> expression, object htmlAttributes)
    {
        string name   = ExpressionHelper.GetExpressionText(expression);
        ... rest of code here
    }

The magic comes from System.Web.Mvc.ExpressionHelper.GetExpressionText(). Once you have the name from your expression, you can apply it to your div.

GetExpressionText()

Answer 2

Try something like this (adapted from working code):

public static IHtmlString DateTimePickerFor<TModel, TValue>(
    this HtmlHelper<TModel> helper,
    Expression<Func<TModel, TValue>> expression,

    // other input parameters as needed

) {
    // metadata gives you access to a variety of useful things, such as the
    // display name and required status
    var metadata = ModelMetadata.FromLambdaExpression( expression, helper.ViewData );
    string markup = ""; // markup for your input            

    var name = helper.NameFor( expression ); // getting the name

    return MvcHtmlString.Create( markup  );
}