I'm using Dapper against a database where strings are stored primarily in `VarChar` columns. By default Dapper uses `NVarChar` parameters when generating queries and while I can wrap each and every string parameter I use with `DbString` it'd be great to use AnsiStrings by default and use `DbString` for the `NVarChar` case.

I tried changing the type map in the Dapper source from `DbType.String` to `DbType.AnsiString` however that seems to cause an error in the IL generation for the parameters delegate (throws an `InvalidProgramException`).

Is there an easier way to do this?

**Update**

Just changing the typeMap was not sufficient I needed to alter some `if (dbType == DbType.String)` checks too. Now it works!