用Dapper添加数据报异常
异常如下：
Dapper.SqlMapper.ExecuteCommand(IDbConnection cnn, IDbTransaction transaction, String sql, Action`2 paramReader, Object obj, Nullable`1 commandTimeout, Nullable`1 commandType) in G:\VS项目\WebApplication1\MySolution\MvcDemo3\Dapper\SqlMapper.cs:1926
Dapper.SqlMapper.Execute(IDbConnection cnn, String sql, Object param, IDbTransaction transaction, Nullable`1 commandTimeout, Nullable`1 commandType) in G:\VS项目\WebApplication1\MySolution\MvcDemo3\Dapper\SqlMapper.cs:710
