Define crisp for semantics for what makes a pagemodel a pagemodel

[rynowak]

Consider the following:

public class MyModel
{
    [FromRoute]
    public int Value { get; set; }
}

@page
@model MyModel

@functions {
    public Task OnPostAsync(...) { ... } // Should this run?
}

Right now the decision depends on whether or not MyModel has a handler method. This is kinda haphazard 😞

We need to define this semantic clearly.

Idea:

• Naming convention based on *Model naming
• An attribute for a base class that says "all derived classes are pagemodels"
• Put that attribute on PageModel.

This is pretty similar to what we do for controllers and VCs

[rynowak]

No one has complained.. Let's move this to preview3

[Eilon]

Discussed with @rynowak and we think that we should drop the naming convention for now.

We should just use the attribute, or any base class that has the attribute.