Why is ?.Any() classed as a nullable bool?

Question

I have the following code:

if (Model.Products?.Cards?.Any())
{
}

If I try this it throws an error:

Cannot convert bool? to bool

Having searched for this this I'm not sure why the error is thrown, where as it will allow me to do

if (Model.Products?.Cards?.Count > 0)
{
}

Why am I unable to use .Any() in this case - why is it classed as a nullable bool yet the count isn't a nullable int?

Answer 1

Simply because it is valid do a greater than on a Nullable<int> and int :

if (null > 0)
{
}

null is considered a Nullable<int> here, and comparing Nullable<int> with int is okay. (Required reading: How does comparison operator works with null int? )

But not a if (null) . An if statement required a boolean.

The required workaround could be:

if (Model.Products?.Cards?.Any() ?? false)
{ }