Example. This example program specifies a file on the disk. To have it run correctly, change the filename to one that exists. ReadAllLines gets a string array from the file. The string array returned can be used as any other string array.
Then: We can use "foreach" or "for" to loop over the file's data in a clean and intuitive way.
Tip: This program reads in a file, counts its lines, and counts all chars in each line.
C# program that calls File.ReadAllLines
using System;
using System.IO;
class A
{
static void Main()
{
string[] lines = File.ReadAllLines("C:\\rearrange.txt");
Console.WriteLine("Length: {0}", lines.Length);
Console.WriteLine("First: {0}", lines[0]);
int count = 0;
foreach (string line in lines)
{
count++;
}
int c = 0;
for (int i = 0; i < lines.Length; i++)
{
c++;
}
Console.WriteLine("Count: {0}", count);
Console.WriteLine("C: {0}", c);
}
}
Output
Length: 430
First: /_1=D1
Count: 430
C: 430
Implementation. The File.ReadAllLines method is not a low-level implementation. Instead, it uses a List and the StreamReader type, and then ToArray, to return the array. This is inefficient if you want to put a file into a List.