I/O Problems

[C++...guy]

Hi all!
Im new to c++ but I used to use c# and made the transition for standalone .exe files.

Im working on a program that uses I/O and I get errors when trying to open, and write to a file with concatenated parameters.

E.g

	ofstream file;
	file.open("C:\\" + textBox->Text + ".txt");
	file << textBox2->Text;
	file.close();

The compiler has an error for the opening and writing line of my code.
The errors say

Cannot convert parameter 1 from 'System::String ^' to 'const wchar_t *'

"No user-defined-conversion operator available,                    
 or Cannot convert a managed type to an unmanaged type"

and it also has an error that might be resolved with the first one

<< illegal for class

I tried to add as much detail as I could :S

Thanks for any help

Kieran