CODEWITHSUNDEEP
c#asp.net-mvcasp.net-mvc-3asp.net-mvc-4razor
xam developer
xam developer

Reputation: 1983

Using Extension Methods in ASP.NET MVC

I am new to ASP.NET MVC. I have inherited a code base that I am trying to work with. I have a need to add some basic HTML attributes. Currently, in my .cshtml file, there is a block like this:

@Html.DropDown(model => model.SomeValue, Model.SomeList)

This references a function in Extensions.cs. This function looks like the following:

public static MvcHtmlString DropDown<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IEnumerable<string> items, string classes = "form-control")
{
  var attributes = new Dictionary<string, object>();
  attributes.Add("class", classes);

  return System.Web.Mvc.Html.SelectExtensions.DropDownListFor(html, expression, itemList.Select(x => new SelectListItem() { Text = x.ToString(), Value = x.ToString() }), null, attributes);
}

I now have a case where I need to disable the drop down in some scenarios. I need to evaluate the value of Model.IsUnknown (which is a bool) to determine whether or not the drop down list should be enabled or not.

My question is, how do I disable a drop down list if I need to? At this point, I do not know if I need to update my .cshtml or the extension method.

Thank you for any guidance you can provide.

Upvotes: 0

Views: 2298

Answers (1)

Ehsan Sajjad
Ehsan Sajjad

Reputation: 62488

Add an optional parameter in your extension method for disabling named enabledand bydefaut it will be true and from view pass bool parameter to disable or enable it:

public static MvcHtmlString DropDown<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, IEnumerable<string> items, string classes = "form-control",bool enabled=true)
{
  var attributes = new Dictionary<string, object>();
  attributes.Add("class", classes);
  if(!enabled)
     attributes.Add("disabled","disabled");

  return System.Web.Mvc.Html.SelectExtensions.DropDownListFor(html, expression, itemList.Select(x => new SelectListItem() { Text = x.ToString(), Value = x.ToString() }), null, attributes);
}

and now in View:

@Html.DropDown(model => model.SomeValue, Model.SomeList,enabled:false)

Upvotes: 6

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