rework GetPageCountAsync as an extension method

[adamfoneil]

Dapper.QX/Dapper.QX/PageableQuery.cs

Line 22 in 9b3c7fe

public async Task<int> GetPageCountAsync(IDbConnection connection, int newPageSize = 0)

This would make it work with any Query<T>. As it is, you have to use PageableQuery<T> as base type.

[adamfoneil]

There will need to be a way to clear the Page property on a query, which means the extension method must attach to something that knows about a Page property. This means there's either an interface requirement or a delegate you have to pass that clears any Page property (or whatever you chose to name it) on your query. The added interface dependency undermines an extension method's usability

[adamfoneil]

This could also possibly work by modifying the query's SQL to remove the {offset} token. That way, I wouldn't have to worry about clearing a Page property -- I could just not see the offset injector and run a "pageless" query to get the page count.

[adamfoneil]

If you're going to remove the {offset} token, it would be better to remove the whole ORDER BY clause itself for the performance benefit. Sorting is expensive, particularly when you don't care about the order in this case because want only a record count.