C#: Cannot locate System libraries -

i have looked in regedit , found running .net version 4.5.1 , therefore libraries after should available me.

i try include namespaces:

using system.io.memorystream; using system.media.soundplayer; 

however vs complains namespaces not exist.

the reference pages memorystream , soundplayer dictate these should available in version of .net. how can fix this?

you confusing class names , namespaces , possibly using directive using statement.

system.io namespace. it's grouping construct used logically group classes , structs , avoid name clashes. system.io.memorystream class inside system.io namespace.

if want use memorystream can either:

var ms = new system.io.memorystream(...); 

or, avoid verbosity of specifying namespace (a full qualified name), can use using directive:

using system.io; 

and can use class name:

var ms = new memorystream(...); 

you can think of using directive telling compiler search paths use when looking class. if ask memorystream it's going first in current namespace class named memorystream, if doesn't find one, it's going in namespaces have been imported using directive (in vb.net, believe equivalent directive called imports which, arguably, makes more sense, there go). if still doesn't find memorystream class you'll compile time error.

note: you'll compile time error if finds more 1 memorystream because won't stop on first 1 - classes need unambiguous. , reason not stuff lot of unneeded using directives @ top of every .cs file. memorystream isn't particularly problem here (i think it's memorystream in bcl), class in system.io path. there several classes called path in bcl (there 1 under system.windows.shapes) , without namespaces they'd nightmare use.

now, confusion might come using statement used classes implement idisposable ensure disposed. memorystream implement idisposable you'll see things like:

using (var ms = new memorystream(...)) {    // code here } 

or, if haven't used using directive declare namespace:

using (var ms = new system.io.memorystream(...)) {     // code here. } 

which looks lot trying using directive.

when looking @ class in msdn there 2 important things need for:

namespace: system.io

assemblies: mscorlib (in mscorlib.dll) system.io (in system.io.dll)

namespace tells need include either in using directive or part of qualified class name in order use class. assemblies part tells assemblies need add references projects in order able use classes. in case memorystream part of core libraries, aren't not have reference required assemblies.