Garbage Collector, Managed Heap etc.

Preamble:
Please do not move this thread on "Windows programming" cause I am a C programmer under Linux who needs to make some code also under Windows but this question IS NOT on strictly-Windows matters. It is instead about Garbage Collector and Managed Heap Objects and variables, which is somethiong more general than just Windows matters.

Problems:
(1) When I alloc on the Managed Heap a new instance of var/obj. with something similar to

Code:

public ref class Form1 : public System::Windows::Forms::Form
{
public:
  InitializeComponent();
  Initialize();
}
..
..
   private: System::String^ Str;
..
..
void Initialize(void)
{	
..
   this->Str = gcnew System::String("");

is there a method I can call to explicitely free the resource when not needed or do I have to let this be done by the garbage collector?

(2)
In another example

Code:

private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e) 
{
  System::String^ TempStr;
..
..
  TempStr=String::Format("DataLen= {0:D}\n",Req.DataLen);
  textBox4->AppendText(TempStr);
..
..

I did not have to use gnew cause this is implicitely called (I have been told in another thread) by String::Format
Where is it easy to the find the answer to this question: a method calls implicitely gcnew or not?

Sorry, this is C++/CLI, not C (and does it really matter where the thread is located?).

For 1) I don't know if there is one or not, but I do not think it's recommended that you do it manually.
As for 2) What does it matter? String is a class and handles its internal memory management by itself. This is standard C++, even without it being managed.

The arrogancy of telling the mods not to move C++/CLI code from the C forums is pretty stunning. If you don't even know what language you're writing in, what kind of programmer are you?