Optionally disable element rendered via MVC

Question

I've got a textbox element which is being rendered inside of my .ascx file using MVC's mark-up:

<%= Html.TextBoxFor(model => model.AssignedOperatorDisplayName, new
    {
        @class = "assignedOperatorDisplayNameTextArea"
    })
%>

I now need to conditionally disable this textbox element. Initially, I attempted to do so by setting the disabled attribute to true or false:

<%= Html.TextBoxFor(model => model.AssignedOperatorDisplayName, new
    {
        @class = "assignedOperatorDisplayNameTextArea",
        disabled = Model.IsElementDisabled()
    })
%>

Unfortunately, this does not work because the browser interprets the presence of the disabled attribute as "true" regardless of whether its value is set to true or false as seen here: http://jsfiddle.net/zWQbL/

So, I'm left wondering how to do this. I was playing around with merging two anonymous objects together using the following article: Merging anonymous types but this isn't working and it feels really wrong.

Any ideas?

EDIT: I'm went with this answer, but there are a few ways to achieve the result. I'd encourage anyone looking at this to consider there needs before using one solution over another.

<%= Html.TextBoxFor(model => model.AssignedOperatorDisplayName, new Dictionary<string, object>()
{
    {
        "class", "assignedOperatorDisplayNameTextArea"
    }
}.WithAttrIf(Model.IsTaskComplete(), "disabled", "true"))%>   

public static Dictionary<string, object> WithAttrIf(this Dictionary<string, object> dictionary, bool condition, string attrname, object value)
{
    if (condition)
        dictionary[attrname] = value;

    return dictionary;
}

Answer 1

Use a ternary operator to conditionally assign the HTML attributes.

<$= Html.TextBoxFor(model => model.AssignedOperatorDisplayName, 
    Model.IsElementDisabled() ? 
        (object)new 
        {
            disabled="disabled", 
            @class = "assignedOperatorDisplayNameTextArea" 
        } :
        new { @class = "assignedOperatorDisplayNameTextArea" })