Can AnsiStrings be used by default with Dapper?

To use ansistrings by default I had to (referring to Dapper 1.3 source from NuGet):

• Alter the type map to use DbType.AnsiString on L164 instead of DbType.String
• In the method CreateParamInfoGenerator change the checks on L960, L968, L973 to include DbType.AnsiString as well as DbType.String.

The problem with the invalid IL seemed to be that the later branch of the code on L1000 checks for typeof(string) whereas the preceeding branches use DbType.

Doing that everything is peachy again - no more index scans!

You can accomplish this without modifying the source code.

Dapper.SqlMapper.AddTypeMap(typeof(string), System.Data.DbType.AnsiString);

Setting this once will adjust all of your strings to varchar.