In 4.7rc, use HasProperty; so: Model.HasProperty("PageTitle")

In 4.7 [final], when a property doesn't exist, DynamicNull will be returned, so you can use one of these three:

1) Model.someProperty.GetType() == typeof(DynamicNull)

2) Model.someProperty.IsNull() [true]

3) Model.someProperty.HasValue() [false]

2 & 3 That doesn't seem to work as expected:

@Model.someProperty.HasValue

Gives me false - which is correct

Then 

@Model.someProperty.HasValue()

Gives an error: Cannot invoke a non-delegate type

Also, when the property does exist:

@Model.PageTitle.HasValue

(also tried with HasValue() ) 

Gives me the error: 'string' does not contain a definition for 'HasValue'

The same behaviour occurs when using IsNull.

The only thing that works reliably is using the first method (GetType()).

So right now HasValue and IsNull can only be used when you're sure that the property does NOT exist, which is backwards.. ;-)

I was using the RC: 1.0.4087.21620 - changeset: 7f84eb55e573

Just to make sure, I upgraded to the latest changeset: 1.0.4089.21758 - changeset: c2a5ffd2c4e7  

But the behaviour is the same still.

They are most likely getters instead of methods, which means my first post was wrong.

I will need to implement IsNull and HasValue on DynamicNode as well as DynamicNull, to allow you to use it regardless of if you get a DynamicNull or not.

This is a really quick patch, in fact, i'll go get my laptop and do it and commit it in the next 30 min, so you can retest. Don't know when the final is coming out and would like this one fixed

Excellent! Final coming out in about 12-24 hours according to Niels on Twitter just now! :)

I just realised, if you have a native type, e.g. string, i'm going to have to put them on there as extension methods - to get the seemless test like you're after..

Shouldn't be too difficult, there's only about 6 or 7 possible types at the moment

Ah yes, that works fine, that's a good check as well. But I would like it if HasValue would check if the prop exists AND has a value, as you will want to do that a lot of the time (a bit like string.IsNullOrEmpty).

Have been playing around, don't think it's going to be possible

I can't get the extension methods to be available on the types (string, etc) from razor - (and i had to change them to be methods not getters)

It's easy enough to add them to my own types (DynamicNode, DynamicMedia etc) but when you have an actual property, it's going to be a native type

Shame! But .HasProperty(string) works great, so I'll stick with that. It's much easier to read and understand than the GetType() version anyway.

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