mysql - 索引超出范围。必须是非负数且小于集合的大小

Question

我有以下代码来获取对象中的表数据，但出现错误，我不知道哪里错了。

    public List<ModelGetEmployeeList> GetEmployeeList()
            {

               List<ModelGetEmployeeList> empList = new List<ModelGetEmployeeList>();
                DataTable dt = new DataTable();

                string q = "select uid,fname,lname from nworksuser;";
                MySqlCommand cmd = new MySqlCommand(q,conn);
                MySqlDataAdapter adapter = new MySqlDataAdapter(cmd); ;
                conn.Open();
                adapter.Fill(dt);
                conn.Close();
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    foreach (DataRow row in dt.Rows)
                    {
                        //Here I am getting following error
                        // Index was out of range. Must be non-negative and less than the size of the collection.
                        empList[i].uid = row["uid"].ToString();
                        empList[i].fname = row["fname"].ToString();
                        empList[i].lname = row["lname"].ToString();
                    }
                }
                return empList;
            }

而 ModelGetEmployeeList 类是这样的-

public class ModelGetEmployeeList
    {       
        public string uid { get; set; }
        public string fname { get; set; }
        public string lname { get; set; }
    }

Answer 1

因为你的 empList 是空的。

将 ModelGetEmployeeList 添加到列表的正确方法是:

ModelGetEmployeeList employee;

foreach (DataRow row in dt.Rows)
{
    employee = new ModelGetEmployeeList();
    employee.uid = row["uid"].ToString();
    employee.fname = row["fname"].ToString();
    employee.lname = row["lname"].ToString();

    empList.Add(employee);
}