C＃asp.net从另一个列表创建字符串列表，该列表返回类对象的列表

Question

I have a list which returns class objects. For dropdownlist data bind purpose I need to create string list from previous list. My main requirement is I need to get two fields(datavalue,datatext) to the dropdownlist from database. Can someone help me to do this

class RoleData
{
    public string id { get; set; }
    public string value { get; set; }
}

private List<RoleData> EmpRoleDataBind(){
        List<RoleData> RoleList = new List<RoleData>();
        if (conn.State.ToString() == "Closed")
        {
            conn.Open();
        }
        string query = "select emp_role_id,description from emp_role";
        MySqlCommand cmd = new MySqlCommand(query,conn);
        MySqlDataReader msdr = cmd.ExecuteReader();

        while (msdr.Read())
        {

            RoleList.Add(
                new RoleData()
                {
                    id = Convert.ToString(msdr["emp_role_id"]),
                    value = Convert.ToString(msdr["description"])
                }    
            );
        }
        msdr.Close();
        conn.Close();
        return RoleList;
    }

Answer 1

You can bind the DropDownList to your list and assign the class property names to DropDownList attributes DataValueField , and DataTextField

dropdownlist1.DataSource = EmpRoleDataBind();
dropdownlist1.DataValueField = "id";
dropdownlist1.DataTextField = "value";
dropdownlist1.DataBind();

As a additional Note

• You probably need to capitalize the first letter of Property, see MSDN article Property Naming Guidelines .
• As the method EmpRoleDataBind returns list of Employee-Role records, I would name it GetEmpRoleData instead of EmpRoleDataBind as It does not bind the DropDownList .