トランザクション

 try
 {
     using (var tran = con.BeginTransaction())
     {
         try 
         { 
             con.Execute("insert into t1 values (1, 'ABC');");
             tran.Commit();
         }
         catch (Exception e)
         {
             tran.Rollback();
         }
     }
 }
 finally
 {
     con.Execute("drop table t1");
 }

参考

• http://msdn.microsoft.com/ja-jp/library/86773566(v=vs.110).aspx
• https://github.com/SamSaffron/dapper-dot-net/blob/master/Tests/Tests.cs