Glass Error opening Experience Editor (ObjectToSwitchTo)

Question

I'm using @Html.Glass().Editable(Model, x => x.MyProperty) for some of our single-text / rich text fields. When I load the site with this code in the view everything looks fine. However, when I open the Experience Editor I see this error:

Value cannot be null. Parameter name: objectToSwitchTo.

   at Sitecore.Diagnostics.Assert.ArgumentNotNull(Object argument, String argumentName)
   at Sitecore.Common.Switcher`2.Enter(TValue objectToSwitchTo)
   at Glass.Mapper.Sc.GlassHtml.MakeEditable[T](Expression`1 field, Expression`1 standardOutput, T model, Object parameters, Context context, Database database, TextWriter writer)

I've seen a few other SO threads about this but no real solutions for me. I'm using a data source set on the rendering. I've stepped through the entire process and don't see any null attributes in my model after using GetDataSourceItem<MyClass>. However, one thing I noticed is that my Sitecore ID field is all zeroes. I saw a different error prior to this, saying I needed to add a Sitecore ID field to my model, so I did. My code for the ID field is as follows:

    [SitecoreId]
    public virtual Guid Id { get; }

My Glass version is 4.5.0.4 which I believe is still pretty recent.

Answer 1

The fact I was getting an empty ID made me think that maybe Glass wasn't able to set the item ID on the property, so I changed my field definition from:

[SitecoreId]
public virtual Guid Id { get; }

to:

[SitecoreId]
public virtual Guid Id { get; set; }

Now things are working fine.