Reading Files using File Methods

There are two additional methods of reading files which are significantly shorter in terms of syntax.

Consider a file called "text.txt" which has the following content:

text.txt

First

Second

Third


              123
            
First
Second
Third

File.ReadAllText Method

We can use the File.ReadAllText to retrieve all the text from a file at once:

index.cs

string text = File.ReadAllText("C:/Users/Admin/Desktop/text.txt");

Console.WriteLine(text);


              12
            
string text = File.ReadAllText("C:/Users/Admin/Desktop/text.txt");
Console.WriteLine(text);

Output:


9
1
2
3
First
Second
Third

File.ReadAllLines Method

The File.ReadAllLines method retrieves all text as well, however it returns data in the form of a string array where each element is an individual line from the file:

index.cs

string[] lines = File.ReadAllLines("C:/Users/Admin/Desktop/text.txt");

foreach(string line in lines) {

Console.WriteLine(line);

}


              12345
            
string[] lines = File.ReadAllLines("C:/Users/Admin/Desktop/text.txt");

foreach(string line in lines) {
    Console.WriteLine(line);
}

Output:


9
1
2
3
First
Second
Third

The difference between StreamReader and the File methods is that with StreamReader we have more control over how many lines and which lines we want to read from the file. For-example if there's a file with over a million lines and we want to retrieve only the first 1000 lines or some specific lines from the middle of the file then in that case using StreamReader will be much more efficient.

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