c# - How to turn an IEnumerable (without type) into an IQueryable<T>? -

having used linq quite bit stumbling on basic task today:

having iqueryable<t> out of ienumerable (without type specified).

specifically want query on parameters of sqlparametercollection. deriving idataparametercollection, ilist, icollection, ienumerable described here. however, these without type specified.

thus question boils down to: how use linq query on sqlparametercollection?

here's have done (the compiler did not complain):

iqueryable<sqlparameter> queryable =      sqlcommand.parameters.asqueryable().cast<sqlparameter>();     //throws argumentexception "source not ienumerable<>" 

note: have searched quite bit, talking ienumerable<t> easy query using asqueryable() of course.

i interested in reason why want this. should explained:

public iqueryable<t> asqueryable<t>(ienumerable list) {     return list.cast<t>().asqueryable();    } 

call this:

iqueryable<sqlparameter> query = asqueryable<sqlparameter>(sqlparametercollection);