C#

commandText = "SELECT user from UserTable where id = @username"
SqlCommand command = new SqlCommand(commandText, connection);
command.Parameters.AddWithValue("@username", tbUser.Text);

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT Age, Description FROM myTable WHERE ID = @ID", con))
        {
        cmd.Parameters.AddWithValue("@ID", myTextBox.Text);
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            while (reader.Read())
                {
                int age = (int) reader["Age"];
                string desc = (string) reader["Description"];
                Console.WriteLine($"{age}\n{desc}");
                }
            }
        }
    }

Pete O'Hanlon wrote:

And what happens if the database is not SQL Server? What if the textbox is an ASP.NET Core one? You are making a lot of assumptions with your answer.

using (SqlConnection con = new SqlConnection(strConnect))
using (IDbCommand cmd = con.CreateCommand())
{
   cmd.CommandText = "bla"; 
   con.Open(); // as late as possible

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT Age, Description FROM myTable WHERE ID = @ID", con))
        {
        cmd.Parameters.AddWithValue("@ID", myTextBox.Text);
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            while (reader.Read())
                {
                int age = (int) reader["Age"];
                string desc = (string) reader["Description"];
                Console.WriteLine($"{age}\n{desc}");
                }
            }
        }
    }

Member 14652449 wrote:

whenever i click on button a new flow rate value is obtained which should to be updated on the graph

public async Task<IList<CompanyHeaderEntity>> GetCompanyHeadersAsync(Predicate<Company> predicate)

where !c.DeletedDT.HasValue && predicate(c)

private void FrmMain_Shown(object sender, EventArgs e)
    {
    TextBox tb = new TextBox();
    ...
    myPictureBox.Controls.Add(tb);
    }

if (myPictureBox.Controls.Count > 0)
    {
    if (myPictureBox.Controls[0] is TextBox tb)
        {
        tb.Enabled = true;
        tb.Enabled = false;
        myPictureBox.Controls.Remove(tb);
        }
    }