Esto debería funcionar:
public string CallCardDetails(string CallCardNo)
{
//initialize
using (DataSet ds = new DataSet())
{
//connect
using (OracleConnection conn = new OracleConnection("User Id=oraDB;Password=ora;Data Source=CCT"))
{
// Oracle uses : for parameters, not @
string query = "SELECT idcard from CallCardTable where idcard= :pCallCardNo";
// Let the using block dispose of your OracleCommand
using (OracleCommand cmd = new OracleCommand(query, conn))
{
// Note: be careful with AddWithValue: if there's a mismatch between the .NET datatype of
// CallCardNo and the idcard column you could have an issue. Cast the value you provide
// here to whatever is closest to your database type (String for VARCHAR2, DateTime for DATE, Decimal for NUMBER, etc.)
cmd.Parameters.AddWithValue(":pCallCardNo", CallCardNo);
conn.Open();
// Again, wrap disposables in a using or use try/catch/finally (using will dispose of things in case of exceptions too)
using (OracleDataAdapter dA = new OracleDataAdapter(cmd))
{
dA.Fill(ds);
return ds.GetXml();
}
}
}
}
}
Editar:agregado usando bloque alrededor del conjunto de datos.
