C++ Windows Forms textBox does not output string. What to do?

Question

C++ / C#

private: void generation(int n,int counter_open,int counter_close, System::String^ ans){
if (counter_open + counter_close == 2 * n){
//pole - textBox
pole->Text+= ans->ToString() ;
pole->Text+=Environment::NewLine+"";
return;
}
}