Question

ok so i have a text box and a button where i will enter a number and press the button. I then want a message box to display if the value has been found or not.

I put all my functions in a model class then call them for the GUI part.
heres what i tried so the sql function (ticket is the name of the table and ID is the value im trying to find):

  public void rebateslip(int ticketID)
    {
        SqlCommand myCommand  = new SqlCommand("SELECT ID FROM ticket WHERE ID = @ticketID", con);
        SqlDataAdapter sqlDa = new SqlDataAdapter(myCommand);

        myCommand.Parameters.AddWithValue("@ID", ticketID);


    }

and than for the button event handler i have this:

 private void buttonPrintRebateSlip_Click(object sender, EventArgs e)
    {

            if (textBoxRebateSlip = model.rebateslip(ticketID)
            {
                MessageBox.Show("Found ticket");
            }
            else
            {
                MessageBox.Show("Ticket not in database");
            }

    }

but it says ticketID does not exist

Answer 1

you should change your model.rebateslip method so that it return a bool, and execute your command, then it should look more or less like this: (don’t have the SqlCommand methods in mind, nor the reader’s ones, but according to my memory it looks like this)

public bool rebateslip(int ticketID)
{
    SqlCommand myCommand  = new SqlCommand("SELECT ID FROM ticket WHERE ID = @ticketID", con);
    SqlDataAdapter sqlDa = new SqlDataAdapter(myCommand);

    myCommand.Parameters.AddWithValue("@ticketID", ticketID);
    var reader = myCommand.Execute();
    return reader.HasRows;    
}

then you should do something like @Ezekiel said in his answer:

int id;
if (!int.TryParse(textBoxRebateSlip.Text, out id)) return;

if (model.rebateslip(id))
...