C++ .NET WebClient freezes GUI -

C++ .NET WebClient freezes GUI -

i made app using webclient class. started freezing gui on first downloadstringasync method call, other downloadstringasync calls going fine. have read topics webclient's freezing, suggestion set webclient->proxy nullptr. , did month ago , helped! but, today has occured webclient->proxy = nullptr line in form's constructor. here performance wizard's report:

as can see, system.net.webclient.downloadstringasync(class system.uri,object) takes best of time (about 5-7 secs). here execute function calls downloadstringasync method:

void execute(string^ method, string^ params, int userdata) { web1->downloadstringasync(gcnew uri("http://<address>" + method + "?" + params + "&access_token=" + token + "&sig=" + md5("/method/" + method + "?" + params + "&access_token=" + token + secret)), userdata); }

maybe know why happening.

c++ .net webclient