Dapper必须声明标量变量

Question

尝试在Dapper中使用参数化查询时遇到问题。我发现其他一些用户遇到类似问题，但无法解决问题。

代码

    public User GetUser(int employeeId)
    {
        var args = new
        {
            EmployeeId = employeeId
        };

        const string sql = @"
                    select 
                        first_name 'FirstName', 
                        last_name 'LastName'
                    from 
                        users 
                    where 
                        employee_id = @EmployeeId 
                ";

        using (var con = MakeConnection())
        {
            var r = con.Query<User>(sql, args);
            return r.FirstOrDefault();
        }
    }

错误

A first chance exception of type 'System.Data.Odbc.OdbcException' occurred in System.Data.dll

Additional information: ERROR [42000] [Microsoft][ODBC SQL Server Driver][SQL Server]Must declare the scalar variable "@EmployeeId".

我也尝试过使用DynamicParameters并传递它，但这不起作用

var p = new DynamicParameters();
p.Add("@EmployeeId", employeeId); // I have also tried without the @
//...
var r = con.Query<User>(sql,p);