Error Running a query with npgsql + Dapper in postgresql

Question

I can capture my "user" object that has inside of itself a "Login and a Password" and, when executing the function by my ORM, I catch the following error message:

{"42883: operator does not exist: @Character Varying"}.

Would anyone know what could be causing such a mistake? Below is the function to execute the query..

  public Usuario Login(Usuario user)
  {
      return this._db.Query<Usuario>("SELECT nome, login, senha FROM usuario WHERE login = @Login and senha = @Senha", new { user }).FirstOrDefault();
  }

Answer 1

Your query defines two parameters: @Login and @Senha. They need to be passed through an anonymous object in the method Query:

public Usuario Login(Usuario user)
{
    return this._db.Query<Usuario>("SELECT nome, login, senha FROM usuario WHERE login = @Login and senha = @Senha", new { Login = "login_do_usuario", Senha = "senha_do_usuario" }).FirstOrDefault();
}