Before using a directory, you must first have it. You can use an existing directory if the operating system or someone else had already created one. You can also create a new directory. Directories are created and managed by various classes but the fundamental class is Directory. Directory is an abstract and sealed class. All of its member functions are static, which means you will never need to declare an instance of the Directory class in order to use it.

Besides the Directory class, additional operations of folders and sub-folders can be performed using the DirectoryInfo class.

To create a directory, you can call the CreateDirectory() member function of the Directory class. This member function is available in two versions. One of the versions uses the following syntax:

public:
    static DirectoryInfo ^ CreateDirectry(String ^path);

This member function takes as argument the (complete) path of the desired directory. Here is an example:

E:\Programs\Business Orders\Customer Information

When this member function is called:

1. It first checks the parent drive, in this case E.
   If the drive doesn't exist, because this member function cannot create a drive, the compiler would throw a DirectoryNotFoundException exception
2. If the drive (in this case E) exists, the compiler moves to the first directory part of the path; in this case this would be the Programs folder in the E drive.
   If the folder doesn't exist, the compiler would create it. If that first director doesn't exist, this means that the other directory(ies), if any, under the first don't exist. So, the compiler would create it/them
3. If the first directory exists and if there is no other directory under that directory, the compiler would stop and would not do anything further.
4. If the directory exists and there is a sub-directory specified under it, the compiler would check the existence of that directory.
   If the sub-directory exists, the compiler would not do anything further and would stop.
   If the sub-directory doesn't exist, the compiler would create it
5. The compiler would repeat step 4 until the end of the specified path

The Directory::CreateDirectory() member function returns a DirectoryInfo object that you can use as you see fit.

1. On the (main) form, double-click an unoccupied area of its body
2. Implement its Load event as follows:
   

   System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e)
   {
   	 String ^ strDirectory = L"C:\\Watts A Loan";
   
   	 if( !Directory::Exists(strDirectory) )
   		 Directory::CreateDirectory(strDirectory);
   
   	 String ^ strFilename = strDirectory + L"\\Employees.wal";
   
   	 FileInfo ^ fiEmployees = gcnew FileInfo(strFilename);
   
   	 // If the employees file was not created already,
   	 // then create it
   	 if( !fiEmployees->Exists )
   	 {
   	     StreamWriter ^ stwEmployees = fiEmployees->CreateText();
   
   	     // And create a John Doe employee
   	    try {
   		 stwEmployees->WriteLine(L"00-000");
   		 stwEmployees->WriteLine(L"John Doe");
   	    }
   	    finally
   	    {
   		 stwEmployees->Close();
   	    }
   	 }
   }

3. Display the NewEmployee form and double-click its Create button
4. Implement its Click event as follows:
   

   System::Void btnCreate_Click(System::Object^  sender, System::EventArgs^  e)
   {
   	 String ^ strFilename = L"C:\\Watts A Loan\\Employees.wal";
   	 FileInfo ^ fiEmployees = gcnew FileInfo(strFilename);
   	 StreamWriter ^ stwEmployees = nullptr;
   
   	 // Normally, we should have the file already but just in case...
   	 if( !fiEmployees->Exists )
   		 stwEmployees = fiEmployees->CreateText();
   	 else // If the file exists already, then we will only add to it
   		 stwEmployees= fiEmployees->AppendText();
   				 
   	 try {
   		 stwEmployees->WriteLine(txtEmployeeNumber->Text);
   		 stwEmployees->WriteLine(txtEmployeeName->Text);
   	 }
   	 finally
   	 {
   		 stwEmployees->Close();
   	 }
   
   	 txtEmployeeNumber->Text = L"";
   	 txtEmployeeName->Text = L"";
   	 txtEmployeeNumber->Focus();
   }

5. Return to the (main) form

Before using or creating a directory, you can first check if it exists. This is because, if a directory already exists in the location where you want to create it, you would be prevented from creating one with the same name. In the same way, if you just decide to directly use a directory that doesn't exist, the operation you want to perform may fail because the directory would not be found.

To check whether a directory exists or not, you can call the Directory::Exists() Boolean static member function. Its syntax is:

public:
    static bool Exists(String ^path);

This member function receives the (complete) path of the directory. If the path exists, the member function returns true. If the directory doesn't exist, the member function returns false.

To create a directory, you can call the CreateDirectory() member function of the Directory class.

One of the most routine operations performed in a directory consists of looking for a file. Both Microsoft Windows operating systems and the user's intuition have different ways of addressing this issue. The .NET Framework also provides its own means of performing this operation, through various techniques. You can start by checking the sub-directories and files inside of a main directory.

To look for files in a directory, the DirectoryInfo class can assist you with its GetFiles() member function, which is overloaded with three versions.

1. In the combo box on top of the Properties window, select txtAccountNumber
2. In the Events section, double-click Leave and implement the event as follows:
   

   System::Void txtAccountNumber_Leave(System::Object^  sender, System::EventArgs^  e)
   {
       String ^ strPath = L"C:\\Watts A Loan";
   
       DirectoryInfo ^ diLoans =
            gcnew DirectoryInfo(strPath);
       array<FileInfo ^> ^ aryLoans = diLoans->GetFiles(L"*",
   		SearchOption::AllDirectories);
   
       String ^ strFilename = txtAccountNumber->Text + L".wal";
   	String ^ strFullname = strPath + L"none.wal";
       bool found = false;
   
       for each(FileInfo ^ fle in aryLoans)
       {
           if( fle->Name == strFilename )
           {
               found = true;
               strFullname = fle->FullName;
           }
       }
   
       if( found == true )
       {
           FileStream ^ stmLoans =
   			File::Open(strFullname,
                           FileMode::Open,
                           FileAccess::Read);
           BinaryReader ^ bnrLoans = gcnew BinaryReader(stmLoans);
   
   		txtAccountNumber->Text = bnrLoans->ReadString();
       txtCustomerName->Text = bnrLoans->ReadString();
       txtEmployeeNumber->Text = bnrLoans->ReadString();
       txtEmployeeName->Text = bnrLoans->ReadString();
       txtLoanAmount->Text = bnrLoans->ReadString();
       txtInterestRate->Text = bnrLoans->ReadString();
       txtPeriods->Text = bnrLoans->ReadString();
       txtMonthlyPayment->Text = bnrLoans->ReadString();
   
   	bnrLoans->Close();
   	stmLoans->Close();
       }
   }

3. In the combo box on top of the Properties window, select txtEmployeeNumber
4. On the Properties window, click the Events button and double-click Leave
5. Implement the event as follows:
   

   System::Void txtEmployeeNumber_Leave(System::Object^  sender, System::EventArgs^  e)
   {
       String ^ strFilename = L"C:\\Watts A Loan\\Employees.wal";
       FileInfo ^ fiEmployees = gcnew FileInfo(strFilename);
   
       if(fiEmployees->Exists )
       {
   	 if( txtEmployeeNumber->Text == L"" )
   	 {
                txtEmployeeName->Text = L"";
   	     return;
   	 }
   	 else
   	 {
   	     StreamReader ^ strEmployees = fiEmployees->OpenText();
   	     String ^ strEmployeeNumber, ^ strEmployeeName;
   	     bool found = false;
   
   	     try {
   		 while( strEmployeeNumber = strEmployees->ReadLine() )
   		 {
   	  	     if( strEmployeeNumber == txtEmployeeNumber->Text )
   		     {
   			 strEmployeeName   = strEmployees->ReadLine();
   			 txtEmployeeName->Text = strEmployeeName;
   			 found = true;
   		     }
   		  }
   
   		  // When the application has finished checking the file
   		  // if there was no employee with that number, let the user know
   		  if( found == false )
   		  {
   			 MessageBox::Show(L"No employee with that number was found");
   				 txtEmployeeName->Text = L"";
   				 txtEmployeeNumber->Focus();
   		  }
   	     }
   	     finally
   	     {
   		 strEmployees->Close();
   	     }
    	}
       }
   }

6. Return to the form and double-click the Save button
7. Implement the event as follows:
   

   System::Void btnSave_Click(System::Object^  sender, System::EventArgs^  e)
   {
       String ^ strPath = L"C:\\Watts A Loan\\" + txtAccountNumber->Text + L".wal";
   
       FileStream ^ stmLoan = File::Create(strPath);
       BinaryWriter ^ bnwLoan =
                   gcnew BinaryWriter(stmLoan);
   
       try
       {
           bnwLoan->Write(txtAccountNumber->Text);
           bnwLoan->Write(txtCustomerName->Text);
           bnwLoan->Write(txtEmployeeNumber->Text);
           bnwLoan->Write(txtEmployeeName->Text);
           bnwLoan->Write(txtLoanAmount->Text);
           bnwLoan->Write(txtInterestRate->Text);
           bnwLoan->Write(txtPeriods->Text);
           bnwLoan->Write(txtMonthlyPayment->Text);
           
          txtAccountNumber->Text = L"";
          txtCustomerName->Text = L"";
          txtEmployeeNumber->Text = L"";
          txtEmployeeName->Text = L"";
          txtLoanAmount->Text = L"";
          txtInterestRate->Text = L"";
          txtPeriods->Text = L"";
          txtMonthlyPayment->Text = L"";
   
           txtAccountNumber->Focus();
       }
       finally
       {
           bnwLoan->Close();
           stmLoan->Close();
       }
   }

8. Execute the application to test it
9. First create a few employees as follows:
    

   Employee #	Employee Name
   42-806	Patricia Katts
   75-148	Helene Mukoko
   36-222	Frank Leandro
   42-808	Jennie Lenney

10. Process a few loans
     
11. Close the application