Question

i want to show one database field in a dropdownlist at form load. can anyone tell me how to do it.

please help

Answer 1

As always start by defining your model:

public class Item
{
    public string Id { get; set; }
    public string Label { get; set; }
}

Then your repository:

public interface IRepository
{
    IEnumerable<Item> GetItems();
}

Then implement this repository:

public class MySQLRepository: IRepository
{
    public IEnumerable<Item> GetItems()
    {
        using (var conn = new MySqlConnection("SOME CONNECTION STRING"))
        using (var cmd = conn.CreateCommand())
        {
            conn.Open(); 
            cmd.CommandText = "SELECT id, name FROM items;";
            using (var reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    yield return new Item
                    {
                        Id = reader.GetString(0),
                        Label = reader.GetString(1),
                    };
                }
            }
        }
    }
}

And finally use an instance of this repository in your form to fetch data:

myDDL.DataSource = repository.GetItems();
myDDL.DataValueField = "Id";
myDDL.DataTextField = "Label";
myDDL.DataBind();