Question

By design, why was the value parameter of Html.RadioButton made as a type of object rather than string?

string RadioButton(this HtmlHelper htmlHelper, string name, object value);

Answer 1

That’s because a radio button could have any value and when the helper decides whether it should be checked or not it looks for a corresponding value in the model state.

For example:

<%= Html.RadioButton("foo", 123) %>

and inside the controller you could pass integer value:

ViewData["foo"] = 123;

and the helper will automatically select the radio button. If you have a complex object it would use the Convert.ToString method.