Changing the Connection String at Runtime

   How to change the directory and path of my database location ?

string datapath = @"'D:\SQLite Database\eFillerDB\eFilerDB.DAT";
string metadata = @"metadata= res://*/eFiler.csdl|//*/eFiler.ssdl|res://*/eFiler.msl;
                                provider=System.Data.SQLite;
                                provider connection string='data source='" + datapath;
string conn = metadata;

var config = IdeaBlade.Core.IdeaBladeConfig.Instance;
var keys = config.EdmKeys;

keys.Add(
                new EdmKeyElement
                {
                    Name = "eFilerDBEntities",
                    LogTraceString = false
                    Connection = conn                        
                });

When i try to run this code i get an runtime error saying to check the connection string.

my requirement is only to change the path and directory of the database location at runtime . what is wrong in the above code. 

Please explain, to correct this problem.