The CData ADO.NET Provider for Xero implements two ADO.NET interfaces you can use to retrieve data from Xero: XeroDataAdapter and XeroDataReader objects. Whereas XeroDataAdapter objects retrieve a single result set of all the data that matches a query, XeroDataReader objects fetch data in subset increments as needed.

Using the XeroDataReader

The XeroDataReader retrieves data faster than the XeroDataAdapter because it can retrieve data in pages. As you read data from the XeroDataReader, it periodically requests the next page of results from the data source, if required. This causes results to be returned at a faster rate. The following example selects all the columns from the Contacts table:

C#

string connectionString = "InitiateOAuth=GETANDREFRESH;";

using (XeroConnection connection = new XeroConnection(connectionString)) {
  XeroCommand cmd = new XeroCommand("SELECT * FROM Contacts", connection);
  
  XeroDataReader rdr = cmd.ExecuteReader();

  while (rdr.Read()) {
    Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["Discount"], rdr["Name"]));
  }
}

VB.NET

Dim connectionString As String = "InitiateOAuth=GETANDREFRESH;"

Using connection As New XeroConnection(connectionString)
  Dim cmd As New XeroCommand("SELECT * FROM Contacts", connection)

  Dim rdr As XeroDataReader = cmd.ExecuteReader()

  While rdr.Read()
    Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Discount"), rdr("Name")))
  End While
End Using