读取连接字符串

using System.Configuration;this.cboxConn.Text.Trim() /// string getValue    class DbConnection    {        private static string currentConnectionString = ConfigurationManager.ConnectionStrings["SalaryManager.Properties.Settings.severConnection"].ConnectionString;        private static string loginConnectionStr = "数据库服务器";        public static string returnConnectionStr()        {            return loginConnectionStr;        }        public static string isServerConnection(string getValue )        {            if (getValue == "数据库服务器")            {                                currentConnectionString = ConfigurationManager.ConnectionStrings["SalaryManager.Properties.Settings.severConnection"].ConnectionString;                        }            else            {                currentConnectionString = ConfigurationManager.ConnectionStrings["SalaryManager.Properties.Settings.localConnection"].ConnectionString;            }            loginConnectionStr = getValue;            return currentConnectionString;        }             public static SqlConnection createConn()        {            SqlConnection thisConnection = new SqlConnection(currentConnectionString);            return thisConnection;        }