How to do a restore of a SQL Server database

The following are the referenced contents: void Restorebutton_click (object sender, System.EventArgs e) { string path = Pathtextbox.text; String dbname = Dbdropdownlist.selectedvalue; String restoresql = "Use master;"; Restoresql + + "RESTORE Database @dbname from disk = @path;"; String pai = "Use master;" ALTER DATABASE Wy SET OFFLINE with ROLLBACK IMMEDIATE; ALTER DATABASE Wy SET ONLINE with ROLLBACK IMMEDIATE "; SqlConnection conn = new SqlConnection (CONNSTR); SqlCommand com1 = new SqlCommand (PAI, conn); SqlCommand mycommand = new SqlCommand (Restoresql, New SqlConnection (ConnStr));     myCommand.Parameters.Add ("@dbname", SqlDbType.Char);     mycommand.parameters["@dbname"]. Value = dbname;     myCommand.Parameters.Add ("@path", SqlDbType.Char);     mycommand.parameters["@path"]. Value = path;     Try     {                      Conn. Open ();                      COM1. ExecuteNonQuery ();                      Conn. Close ();                      MyCommand.Connection.Open ();      mycommand.executenonquery ();                      Infolabel.text = "Restore success!" <br> has restored the backup "+path+" to the database; } catch (Exception ex) { Infolabel.text = "Restore failed!" <br> error message follows:<br> "+ ex. ToString (); } Finally { MyCommand.Connection.Close (); } }