programmmerr

using System.Data;
using System.Data.SqlClient;
using DevExpress.XtraEditors;

// connection string
string connectionString = @"Server=.\SQLEXPRESS;Database=MyDatabase;Trusted_Connection=True;";

private void LoadComboBox()
{
    using (SqlConnection conn = new SqlConnection(connectionString))

programmmerr

private void ClearAllControls()
{
    // Local recursive function to clear controls
    void ClearCollection(Control.ControlCollection controls)
    {
        foreach (Control ctrl in controls)
        {
            // Specific DevExpress controls
            if (ctrl is DevExpress.XtraEditors.ComboBoxEdit combo)
            {

programmmerr

//Όταν περιμένεις πολλές γραμμές:
List<Product> products = new List<Product>();

using (SqlConnection conn = new SqlConnection(connectionString))
{
    string query = @"SELECT ProductId, Name, Price FROM Products WHERE Category = @Category";
    using (SqlCommand cmd = new SqlCommand(query, conn))
    {
        cmd.Parameters.AddWithValue("@Category", categoryName);
        conn.Open();