how can i solve these errors

Apr 6 2016 3:50 AM

Error 1 The best overloaded method match for 'System.Data.Common.DbDataReader.GetString(int)' has some invalid arguments C:\Users\PC-003\Documents\Visual Studio 2012\Projects\graphs\graphs\Form1.cs 55 56 graphs

Error 2 Argument 1: cannot convert from 'string' to 'int' C:\Users\PC-003\Documents\Visual Studio 2012\Projects\graphs\graphs\Form1.cs 55 79 graphs