MVC Dropdown List isn't binding to the model.

Question

Hi, I am trying set up a simple dropdown list but I dont seem to be able to get it to bind to the Model. I am using Asp.Net MVC and nhibernate.

My dropdown list is declared like so:

<%= Html.DropDownListFor(model => model.Project, (IEnumerable<SelectListItem>)ViewData["Projects"], " -- Select -- ", new { name = "Project" })%>

I set up the select list like so:

ViewData["Projects"] = new SelectList(projectRepository.GetAll(), "EntityGUID", "Name", editEntity.Project);

This seems to bind the select list to the Dropdown fine, but the SelectedValue is not set. it shows up as the default --- Select ---

Also when I save this data, the dropdown does not bind to the model, I have to manually set the object like so to save it:

entity.Project = projectRepository.GetById(new Guid(Request["Project"].ToString()));

I believe I have take the correct messures to have this item bind directly to my model. Is there something I am missing here?

Many thanks for your time, Rod

Answer 1

This is just a hunch since your code looks good to me but I don't think you need to include the forth parameter when defining your SelectList. Setting that field might be distrupting the normal flow of things (overriding your model binding) and I have never bound a DropDownList and had the SelectList's SelectedValue set.

Try removing that and see how it goes.

SelectList(projectRepository.GetAll(), "EntityGUID", "Name"); 

Also I asked a question a while back regarding how to implement DropDownList in MVC2 that you might find useful.

Answer 2

OMG I found the problem........

It has taken me 3 days to turn:

<%= Html.DropDownListFor(model => model.Aspect, (IEnumerable<SelectListItem>)ViewData["AspectTypes"])%>

into:

<%= Html.DropDownListFor(model => model.Aspect.EntityGUID, (IEnumerable<SelectListItem>)ViewData["AspectTypes"])%>

model.Aspect*.EntityGUID* I had to bind the drop down to the objects guid, not the object itself. Doh....Im feeling the pain, much work to catch up on.

Thanks for your time.