Zkus to takto:
while ((radek = soubor.ReadLine()) != null)
{
Console.WriteLine(radek);
}A dále se inspiruj třeba tady:
http://csharp.codenewbie.com/articles/csharp/1434/R ead_and_Write_to_a_Text_File-Page_1.html
http://www.codeproject.com/useritems/Read_a_certain _line.asp
http://www.c-sharpcorner.com/UploadFile/ggaganesh/C SAndTypes11092005011259AM/CSAndTypes.aspx