كيف اتعامل مع Connectionstring

السلام عليكم

من البارحة وانا احاول ان اشبك مع

قاعدة البيانات عن طريق ال ConnectionString

فكل المحاولات باتت بالفشل رغم استخدامي لكل هذه الاسطر التالية

// conn.ConnectionString = "User ID=Sa;Password=Sa;Data Source=.;Initial Catalog=Database;";

// conn.ConnectionString = "Data Source=SQL Server DB;Initial Catalog=Database;User ID=You'reUserName;Password=You'rePassword;";

// conn.ConnectionString = "Data Source=.; Initial Catalog=Database; User ID=""; Password=""; ";

// conn.ConnectionString = "Data Source=SQLEXPRESS;AttachDbFilename=Database.mdf;Integrated Security=True;User Instance=True;";

// conn.ConnectionString = "Data Source=\;SQLEXPRESS;AttachDbFilename=@"D:\Documents and Settings\fadi\My Documents\Visual Studio 2005\WebSites\WebSite3\App_Data\Database.mdf";Integrated Security=True;User Instance=True;";

// conn.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename="D:\\Documents and Settings\\fadi\\My Documents\\Visual Studio 2005\\WebSites\\WebSite3\\App_Data\\Database.mdf";Integrated Security=True;User Instance=True;";

conn .ConnectionString ="Data Source=.;SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True;";

conn.ConnectionString ="Data Source=.;SQLEXPRESS;User Instance=True";