Parse error Unexpected (, expected , in php when assign content file to a static property

I
have this
class:

class
            MyClass {
 const DB_NAME = "MyDb";


 const HOST
            = "localhost"; 

 const USER = "abcdef";

 const
            PASSWORD = "ghijklmn";

 public static $MyString =
            file_get_contents('file.txt');

}
?>

I
have no idea what is wrong with file_get_contents
?

I cannot understand what is the error says ?
Why ( is unexpected ?

I
read the following articles but these don't help me to solve that
error:

href="https://stackoverflow.com/questions/11785017/parse-error-syntax-error-unexpected-t-string-in-php">Parse
error: syntax error, unexpected T_STRING in
php

href="https://stackoverflow.com/questions/8353629/parse-error-t-variable">Parse error
T_Variable

href="https://stackoverflow.com/questions/9720861/file-get-contents-shows-unexpected-output-while-reading-a-file">file_get_contents
shows unexpected output while reading a file

Answer

It's because you have assigned expression to
variable declaration. It can only use
constants.

The workaround would be like
this

class
            MyClass {

 ...
 public static $MyString;

            ...
}
MyClass::$MyString =
            file_get_contents('file.txt');