I'm not 100%, but maybe this may help:
var TransferFlag = "N";
var SearchCaseNo = "";
var q_transfer = "";
var q_newcaseno = "";
using (var con = new OdbcConnection("Dsn=XXXXX; User ID=XXXXX; Password=XXXXX"))
{
con.Open();
using (var cmd = new OdbcCommand("SELECT caa443400048 FROM caa44340 WHERE caa44340041 = ?", con))
{
cmd.Parameters.AddWithValue("@var", txtCustomCaseNumber.Text);
q_transfer = (string)cmd.ExecuteScalar();
}
if (!string.IsNullOrEmpty(q_transfer))
{
using (var cmd = new OdbcCommand("SELECT caa44340041 FROM caa44340 WHERE caa443400018 = ?", con))
{
cmd.Parameters.AddWithValue("@var", q_transfer);
q_newcaseno = (string)cmd.ExecuteScalar();
}
TransferFlag = "Y";
SearchCaseNo = q_newcaseno;
MessageBox.Show("This is a transfer");
}
else
MessageBox.Show("This is not a transfer");
}