在ASP.net核心中填充下拉列表

<select id="ddlOptions" runat="server"></select>

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // 获取数据源，可以从数据库、API等获取
        List<string> options = GetOptions();

        // 绑定数据到下拉列表控件
        ddlOptions.DataSource = options;
        ddlOptions.DataBind();
    }
}

private List<string> GetOptions()
{
    // 从数据源获取选项数据
    // 这里假设从数据库获取数据
    List<string> options = new List<string>();
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        string query = "SELECT OptionName FROM OptionsTable";
        SqlCommand command = new SqlCommand(query, connection);
        connection.Open();
        SqlDataReader reader = command.ExecuteReader();
        while (reader.Read())
        {
            options.Add(reader["OptionName"].ToString());
        }
        reader.Close();
    }
    return options;
}

<asp:DropDownList ID="ddlOptions" runat="server"></asp:DropDownList>