How to: Read a Text File One Line at a Time (Visual C#)

This example reads the contents of a text file, one line at a time, into a string using the ReadLine method of the StreamReader class. Each text line is stored into the string line and displayed on the screen.

Example

int counter = 0;  
string line;  

// Read the file and display it line by line.  
System.IO.StreamReader file =   
    new System.IO.StreamReader(@"c:\test.txt");  
while((line = file.ReadLine()) != null)  
{  
    System.Console.WriteLine (line);  
    counter++;  
}  

file.Close();  
System.Console.WriteLine("There were {0} lines.", counter);  
// Suspend the screen.  
System.Console.ReadLine();  

Compiling the Code

Copy the code and paste it into the Main method of a console application.

Replace "c:\test.txt" with the actual file name.

Robust Programming

The following conditions may cause an exception:

  • The file may not exist.

.NET Framework Security

Do not make decisions about the contents of the file based on the name of the file. For example, the file myFile.cs may not be a C# source file.

See Also

System.IO
C# Programming Guide
File System and the Registry (C# Programming Guide)