From Murach c# 2005 - ch. 22

Directory
	-Exists(path)
	- CreateDirectory(path)
	- Delete(path)
File
	- Exists(path)
	- Delete(path)
	- Copy(source, dest)
	- Move(source, dest)
Path

string dir = @c"\temp\";
if (!Directory.Exists(dir))
	Directory.Create(dir)
	
string path = dir + "Products.txt";
if (File.Exists(path))
	File.Delete(path);
	
--
Stream - flow of data from one location to another
text or binary streams

FileStream

StreamReader
StreamWriter

BinaryReader
BinaryWriter

FileMode
	- Append	(creates if doesn't exist)
	- Create 	(overwritten)
	- CreateNew (ex if exist)
	- Open   	(ex if exist)
	- OpenOrCreate
	- Truncate 
	
FileAccess
	- Read
	- ReadWrite	(def)
	- Write
	
FileShare
	- None
	- Read		(def)
	- ReadWrite
	- Write
	
FileStream
	- Close
	
//writing	
string path = @"c:\temp\Products.txt";
FileStream fs = new FileStream(path, FileMode.Create, FileAccess.Write);

//reading
string path = @"c:\temp\Products.txt";
FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);

----------
Exceptions
----------

IOException					(base class)
DirectoryNotFoundException
FileNotFoundException
EndOfStreamException 		(read beyond end of stream)

--

string dirPath = @"c:\temp\"
string filePath = dirPath + "Products.txt";
FileStream fs = null;
try
{
	fs = new FileStream(filePath, FileMode.Open);
	
}
catch(FileNotFoundException)
{
	MesssageBox.Show(filePath + " not found.", "File Not Found");
}
catch(DirectoryNotFoundException)
{
	MesssageBox.Show(dirPath + " not found.", "File Not Found");
}
catch(IOException ioe)
{
	MesssageBox.Show(ioe.Message, "IO Exception");
}
finally
{
	if (fs != null)
		fs.Close();
}

---

StreamWriter
	- Write(data)
	- WriteLine(data)
	- Close()

StreamWriter textOut = 	new StreamWriter(
						new FileStream(path, FileMode.Create, FileAccess.Write));
foreach (Product product in products)
{
	textOut.Write(		product.Code + "|");
	textOut.Write(		product.Description + "|");
	textOut.WriteLine(	product.Price);
}
textOut.Close();

---

StreamReader
- Peek()		//reads w/o advancing to next position in stream
- Read()		// next char
- ReadLine()	// next line
- ReadToEnd()	// current position to the end, usually whole file
- Close() 

StreamReader textIn = 	new StreamReader(
						new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read));
						
List<Product> products = new List<Product>();
while (textIn.Peek() != -1)
{
	string row = textIn.ReadLine();
	string [] columns = row.Split('|');
	
	Product product = new Product();
	
	product.Code = columns[0];
	product.Description = columns[1];
	product.Price = convert.ToDecimal(columns[2]);
	
	products.Add(product);
}
textIn.Close();

---

using System;
using System.IO;
using System.Collections.Generic;

namespace ProductMaintenance
{
	public class ProductDB
	{
		private const string dir = @"c:\temp\"
		private const string file = dir + "Products.txt"
		
		public static List<Product> GetProducts()
		{
			if (!Directory.Exists(dir))
				Directory.Create(dir);
			StreamReader textIn = 	new StreamReader(
						new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read));
						
			List<Product> products = new List<Product>();
			while (textIn.Peek() != -1)
			{
				string row = textIn.ReadLine();
				string [] columns = row.Split('|');
				
				Product product = new Product();
				
				product.Code = columns[0];
				product.Description = columns[1];
				product.Price = convert.ToDecimal(columns[2]);
				
				products.Add(product);
			}
			textIn.Close();	
			
			return products;
		}
		
		public static void SaveProducts(List<Product> products)
		{
			StreamWriter textOut = 	new StreamWriter(
						new FileStream(path, FileMode.Create, FileAccess.Write));
			foreach (Product product in products)
			{
				textOut.Write(		product.Code + "|");
				textOut.Write(		product.Description + "|");
				textOut.WriteLine(	product.Price);
			}
			textOut.Close();

		}	
		
		
	}// end class ProductDB
} //  end namespace ProductMaintenance

------
binary
------

BinaryWriter
	- Write(data)
	- Close()

BinaryWriter binaryOut = new BinaryWriter(
						 new FileStream(path, FileMode.Create, FileAccess.Write));

foreach (Product product in products)
{
	binaryOut.Write(product.Code);
	binaryOut.Write(product.Description);
	binaryOut.Write(product.Price);
}
binaryOut.Close();

---

BinaryReader
- PeekChar()	//reads w/o advancing to next position 
- Read()		// next char - advance to next position
- ReadBoolean()	// boolean - advance one byte
- ReadByte()	// byte - advance one byte
- ReadChar()	// char - advance one Char
- ReadDecimal()	// decimal - advance 16 bytes
- ReadInt32()	// 4-byte signed int - advance 4 bytes
- ReadString()	// string - advances by number of chanacters in the string
- Close() 

BinaryReader binaryIn = new BinaryReader(
						new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read));
						
List<Product> products = new List<Product>();
while (binaryIn.PeekChar() != -1)
{
	Product product = new Product();
	
	product.Code = binaryIn.ReadString();
	product.Description = binaryIn.ReadString();
	product.Price = binaryIn.ReadDecimal();
	
	products.Add(product);
}
binaryIn.Close();

---

using System;
using System.IO;
using System.Collections.Generic;

namespace ProductMaintenance
{
	public class ProductDB
	{
		private const string dir = @"c:\temp\"
		private const string file = dir + "Products.dat"
		
		public static List<Product> GetProducts()
		{
			if (!Directory.Exists(dir))
				Directory.Create(dir);
			BinaryReader binaryIn = new BinaryReader(
									new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read));
						
			List<Product> products = new List<Product>();
			while (binaryIn.PeekChar() != -1)
			{
			
				Product product = new Product();
				
				product.Code = binaryIn.ReadString();
				product.Description = binaryIn.ReadString();
				product.Price = binaryIn.ReadDecimal();
				
				products.Add(product);
			}
			binaryIn.Close();	
			
			return products;
		}
		
		public static void SaveProducts(List<Product> products)
		{
			BinaryWriter binaryOut = 	new BinaryWriter(
										new FileStream(path, FileMode.Create, FileAccess.Write));
			foreach (Product product in products)
			{
				binaryOut.Write(product.Code);
				binaryOut.Write(product.Description);
				binaryOut.Write(product.Price);
			}
			binaryOut.Close();

		}	
		
		
	}// end class ProductDB
} //  end namespace ProductMaintenance