Question

I have been having an issue with updating a nullable bool value using TryUpdateModel. I have a template created to handle the values as so:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<System.Boolean?>" %>


<% if (ViewData.ModelMetadata.IsNullableValueType) { %>
    <%= Html.DropDownListFor(model => model, new SelectListItem[] { new SelectListItem() { Text = "", Value = "null"},new SelectListItem() { Text = "Yes", Value = "true"}, new SelectListItem() { Text = "No", Value = "false"  }})%>
<% } else { %>
    <%= Html.CheckBoxFor(model => model.Value)%>
<% } %>

My View looks like this:

<%=Html.EditorFor(model => model.TestField) %>  //which looks/acts correctly

The SQL Server Database types are also defined correctly as a nullable bit.

My Code is straight forward:

  var so = new SomeObject();
  if (ModelState.IsValid)
  {
      //gets to here
      if (TryUpdateModel(so))
      {
          //never gets here
      }

   }

The Error reported for ModelState on that field is: “The value ‘null’ is not valid for TestField.”

This seems pretty straight forward, but I wasn’t able to find anything on this. Any help would be greatly appreciated.

Cheers,

Brian

Answer 1

Since nobody has answered my question, I will put my workaround up. It’s not super elegant, but it works. If I wanted it to be pretty, it’d be in a pink font. 😉

Basically I had to load “so” (someObject) manually using the form Collection like so…

var so = new SomeObject();
if (ModelState.IsValid)
{

   so.WasItFound = StringToNullBool(form["WasItFound"]);
   so.WhereWasItFound = form["WhereWasItFound"];

   //fill in the rest of the properties using the form Collection...


}



private bool? StringToNullBool(string s)
{
   if (s != "null")
      return Convert.ToBoolean(s);
   else
      return null;
 }