size_t fileSize = 0;
string path = string path = "C:\\Folder1\\Folder2\\OneFile.txt";

ifstream infile(path.c_str());

//if(infile.is_open())
//{
         infile.seekg(0, ios::end); //move to end of file
         fileSize = infile.tellg();
//}
			
	stringstream Getsize;
	std::string Getsize2;
	Getsize << fileSize;
	Getsize2 = Getsize.str();
					 
	String^ sizeee = gcnew String(Getsize2.c_str());
	MessageBox::Show(sizeee);