Hi Can't figure this out - hence the post :) I am using V7.8.1 so models builder is also installed and enabled. I have changed the mode to AppData to allow me to extend the models. This is all good I have a HomeTemp partial class

{
    public string PetName
    {
        get;            set;
    }

    public string CallerName
    {
        get; set;
    }

}

Controller

public class HomeTempSurfaceController : SurfaceController
{
    public ActionResult ShowForm(HomeTemp homeTemp)
    {
        homeTemp.PetName = "Fido";
        return PartialView(viewName: "HomeTempPartial", model: homeTemp);
    }
    public ActionResult HandleFormPost(string submitButton, HomeTemp homeTemp)
    {
        Session["CallerName"] = homeTemp.CallerName;
        Session["PetName"] = homeTemp.PetName;

        return Redirect(homeTemp.Start.Url);
    }
}

And a partial view

@inherits UmbracoViewPage<HomeTemp>

@using (Html.BeginUmbracoForm<VFUmbraco.Controllers.HomeTempSurfaceController>("HandleFormPost"))
{
    <div class="container-fluid">
        <div class="container">
            <label for="CallerName">Caller Name:</label>@Html.EditorFor(x => x.CallerName)
        </div>
    </div>
    <div class="container-fluid">
        <div class="container">
            <label for="PetName">Pet Name:</label>@Html.EditorFor(x => x.PetName)
        </div>
    </div>
    <div class="container-fluid">
        <div class="container">
            <input type="submit" value="Submit" />
        </div>
    </div>
}

The page loads correctly with the textbox field PetName prepopulated with 'Fido'. Which can be edited and caller name can be added. The submit is posting the model to the controller but the model has null values for PetName and CallerName.

Can anyone see what I'm doing wrong? Thanks Alan