hii want read a link from file and use it with the extension of the link ,
the file contain :http://82.212.81.2:888/mob/

and i wanna use it like this:

StreamReader rr = new StreamReader("link.txt");
string sor = rr.ReadLine();
url = "sor+"resources/stdInfo/authenticate/" + tx.Text + "/" + passwordBox1.Password+ "/1/570322308ce1121cba1b93f5acc9ebd4733ef2bca90ef942a2cfa224f0aa08dc/1";


the red : mean the string wich i put into it what i've read from file the green : mean that there's a mistake but i dont know what it's?!! any one can help

You have sor in quotes for a start. Is that a typo or part of your code because it, at the very least, should be:

url = sor + "resources/stdInfo/authenticate/" + tx.Text + "/" + passwordBox1.Password+ "/1/570322308ce1121cba1b93f5acc9ebd4733ef2bca90ef942a2cfa224f0aa08dc/1";

commented: thanx alot:) +1