Advertisement

---

Top

< Prev

Next >

The static File class is defined in the System.IO namespace and it provides us static methods to perform the file manipulation operations such as:

• Creating a file.
• Opening a file.
• Moving a file.
• Deleting a file.
• Copying a file.
• Reading/Writing a file.
• Creating FileStream objects.

File class also allows us to get and set the file specific information such as its creation time, last access time, the last time it was written to.

Some commonly used methods of File class

Methods	Description
FileStream Create(String path)	This method creates or overwrites a file in the specified path and it returns a FileStream object that provides read/write access to the specified file.
FileStream Open(String path, FileMode mode)	This method opens a FileStream on the specified path with read/write access with no sharing. The FileMode value specifies whether a file is created if one does not exist, and determines whether the contents of existing files are retained or overwritten.
void Move(String sourceFileName, String destFileName)	This method moves a specified file to a new location, providing the option to specify a new file name at the destination.
void Delete(String path)	This method deletes the file specified by the path.
void Copy(String sourceFileName, String destFileName)	This method copies an existing file to a new file. You are not allowed to overwrite a file of the same name.
FileStream OpenRead(String path)	This method opens an existing file for reading and it returns a FileStream object that provides read access to the specified file.
FileStream OpenWrite(String path)	This method opens an existing file or create a new file for writing and it returns an unshared FileStream object that provides read access to the specified file.
bool Exists(String path)	This method determines whether the specified file exists or not.
DateTimeGetCreationTime(String path)	This method returns the creation time of the specified file or directory.
void SetCreationTime(String path, DateTime time)	This method sets the creation time the specified file or directory.
DateTime GetLastAccessTime(String path)	This method returns the last access time of the specified file or directory.
void SetLastAccessTime(String path, DateTime time)	This method sets the last access time of the specified file or directory was written to.
DateTime GetLastWriteTime(String path)	This method returns the last access time of the specified file or directory was written to.
void SetLastWriteTime(String path, DateTime time)	This method sets the last time the specified file or directory was written to.
bool Exists(String path)	This method determines whether a specified file exists or not.
String[] ReadAllLines(String path)	This method opens a text file, reads all lines from it and then closes the file.
String[] ReadAllLines(String path, String[] contents)	This method create a new file, writes a String array to it and closes it.

• Using the File class to create a new file and write to it.


In this example, we are going to create a new file by calling the Create() method of File class, which returns us a FileStream object, using which we are going to write to a new file.



//C# Using the File class to create a file and write to it 

using System;
using System.IO;
using System.Text;

class A
{
public static void Main(String[] ar)
{
	 try
	{
		//Calling the Create() method of File
		//Which creates a new specified file 
		//and returns a FileStream object to write to the file 
		FileStream fs = File.Create("D:\\FileEx1.txt");

		//Creating a String object 
		String str = "Live your life to the fullest!";
	
		//Creating a byte array from a String
		byte[] bA = Encoding.ASCII.GetBytes(str);  

		//Writing to a file(one byte a time)
		//using the FileStream object.
		foreach(byte bt in bA)
		{
			//writing one byte at a time to the file.
			fs.WriteByte(bt);	
		}
	
		fs.Flush();
		fs.Close();
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}
}
}





Output is -:


A file called "MyFile1.txt" is created in D: drive, with the contents -:


Live your life to the fullest!






Advertisement






• Using the File class to read an existing file.


In this example, we are going to open an existing file(which was created in the previous example) to read from it, by calling the OpenRead() method of File class, which returns us a FileStream object, using which we are going to read the specified file.



//C# Using the File class to open and read an existing file
//We will call the OpenRead(String path) method of File class
//which returns us the FileStream object to read the file

using System;
using System.IO;

class A
{
public static void Main(String[] ar)
{
	try
	{
		//Calling the OpenRead(String path) method of File
		//which opens the specified path with read access to it
		//and returns a FileStream object to read the file 
		FileStream fs = File.OpenRead("D:\\FileEx1.txt");
	
		int c;
	
	
		//Calling the ReadByte() method of FileStream to reading one byte out of a file
		Console.WriteLine("Reading the contents of a file: ");
		while((c = fs.ReadByte()) !=-1) 
		{
			//Casting byte to char for displaying the read character on the screen
			Console.Write((char)c); 
		}

		//Closing the byte stream i.e. FileStream
		fs.Close();
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}

}
}





Output is -:




Reading the contents of a file:
Live your life to the fullest








• Using the File class to move an existing file.


In this example, we are going to call the Move() method of File class to move an existing file to another location(and also providing it a new name in its new location) Next, we will call the OpenRead() method of File class to open and read the contents of the newly moved file.

Let us move the file MyFile1.txt which we have created in one of our previous example with contents:

Live your life to the fullest!





//C# Using the File to move a file to another location(also providing it a new name)
//Next, we will use the File class to open and read the newly moved file 
//By calling the OpenRead(String path) method of File class
//which returns us the FileStream object to read the file

using System;
using System.IO;

class A
{
public static void Main(String[] ar)
{
	try
	{
		//Calling the Move() method of File
		//which moves a file present in D: Drive to E: Drive and with a new name
		File.Move("D:\\FileEx1.txt", "E:\\E-File1.txt");
	
		//Calling the OpenRead() method of File
		//To read the newly moved file 
		FileStream fs = File.OpenRead("E:\\E-File1.txt");

		int c;
	
		//Calling the ReadByte() method of FileStream to reading one byte out of a file
		Console.WriteLine("Reading the contents of the newly moved file: ");
		while((c = fs.ReadByte()) !=-1) 
		{
			//Casting byte to char for displaying the read character on the screen
			Console.Write((char)c); 
		}

		//Closing the byte stream i.e. FileStream
		fs.Close();
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}

}
}





Output is -:




Reading the contents of the newly moved file:
Live your life to the fullest


Note: Calling the Move() method does not make a copy of a file, it permanently moves a file to a new location.




Advertisement






• Using the File class to copy an existing file.


In this example, we are going to call the Copy() method of File class which copies the content of an existing file to a new file in such a way that it moves an existing file to a new file(which could be at any existing location on your computer).

Next, we will call the OpenRead() method of File class to open and read the contents of the newly made copy of the file.

Let us move the file(E-File1.txt which we have moved to the E: Drive in our last example, with contents:

Live your life to the fullest!





//C# Using the File to copy a file to another location(also providing it a new name)
//Next, we will use the File class to open and read the newly copied file 
//By calling the OpenRead(String path) method of File class
//which returns us the FileStream object to read the file

using System;
using System.IO;

class A
{
public static void Main(String[] ar)
{
	try
	{
		//Calling the Move() method of File
		//which copies a file present in E: Drive to E: Drive's 'New Folder' and with a new name
		File.Copy("E:\\E-File1.txt", "E:\\E-File2.txt");
	
		//Calling the OpenRead() method of File
		//To read the copy of the file 
		FileStream fs = File.OpenRead("E:\\E-File2.txt");

		int c;
	
		//Calling the ReadByte() method of FileStream to reading one byte out of a file
		Console.WriteLine("Reading the contents of the copy of the file: ");
		while((c = fs.ReadByte()) !=-1) 
		{
			//Casting byte to char for displaying the read character on the screen
			Console.Write((char)c); 
		}

		//Closing the byte stream i.e. FileStream
		fs.Close();
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}

}
}





Output is -:




Reading the contents of the copy of the file:
Live your life to the fullest!


Note: When calling the Copy() method, you are not allowed to overwrite an existing file of the same name. Doing so, throws an IOException..






• Using the File class to get the file specific information.


In this example, we are going to call the static methods of File class to get some file specific information such as its creation time, last access time and the last time it was written to.



//C# Using the File to find get and set the file information
//such as its last access time, creating time and last write time.


using System;
using System.IO;

class A
{
public static void Main(String[] ar)
{
	try
	{
		Console.WriteLine("Getting the file specific information about the file 'E-File1.txt' in E Drive");
	
		//Getting the creating time of the specified file
		DateTime d = File.GetCreationTime("E:\\E-File1.txt");
		Console.WriteLine("Creation time of the file: " + d.ToString());
	
		//Getting the last write time of the specified file
		d = File.GetLastWriteTime("E:\\E-File1.txt");
		Console.WriteLine("Last write time of the file: " + d.ToString());

		//Getting the last access time of the specified file
		d = File.GetLastAccessTime("E:\\E-File1.txt");
		Console.WriteLine("Last access time of file: " + d.ToString());
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}

}
}





Output is -:




Getting the file specific information about the file 'E-File1.txt' in E Drive
Creation time of the file: 17-01-2020 13:35:19
Last write time of the file: 17-01-2020 13:01:35
Last access time of file: 17-01-2020 13:49:52








• Using the File class to delete an existing file.


In this example, we are going to call the Delete() method of File class to delete an existing file.



//C# Calling the Delete() method of File class to delete an existing file

using System;
using System.IO;

class A
{
public static void Main(String[] ar)
{
	try
	{
		//Calling the Delete() method of File class to delete an existing file
		File.Delete("E:\\E-File2.txt");
	}
	catch(IOException e)
	{
		Console.WriteLine(e);
	}

}
}



The program when executed, deletes the specified file and using the same method, you could even delete an empty directory. The program may throw an IOException, if the file you want to delete is still in use.

Please share this article -

< Prev

Next >

< C# BinaryReader

C# Directory >

Advertisement