public class DataMatrixGenerator :
    BarCode2DGenerator

Public Class DataMatrixGenerator
    Inherits BarCode2DGenerator

using System;
using System.Collections.Generic;
using System.Drawing.Printing;
using System.Windows.Forms;
using DevExpress.XtraPrinting.BarCode;
using DevExpress.XtraReports.UI;
// ...
public XRBarCode CreateDataMatrixBarCode(string BarCodeText) {
    // Create a barcode control.
    XRBarCode barCode = new XRBarCode();

    // Set the barcode's type to DataMatrix.
    barCode.Symbology = new DataMatrixGenerator();

    // Adjust the barcode's main properties.
    barCode.Text = BarCodeText;
    barCode.Width = 400;
    barCode.Height = 150;

    // If the AutoModule property is set to false, uncomment the next line.
    barCode.AutoModule = true;
    //barcode.Module = 3;

    // Adjust the properties specific to the barcode type.
    ((DataMatrixGenerator)barCode.Symbology).CompactionMode = DataMatrixCompactionMode.Text;
    ((DataMatrixGenerator)barCode.Symbology).MatrixSize = DataMatrixSize.MatrixAuto;

    return barCode;
}

Imports System
Imports System.Collections.Generic
Imports System.Drawing.Printing
Imports System.Windows.Forms
Imports DevExpress.XtraPrinting.BarCode
Imports DevExpress.XtraReports.UI
' ...
Public Function CreateDataMatrixBarCode(ByVal BarCodeText As String) As XRBarCode
    ' Create a barcode control.
    Dim barCode As New XRBarCode()

    ' Set the barcode's type to DataMatrix.
    barCode.Symbology = New DataMatrixGenerator()

    ' Adjust the barcode's main properties.
    barCode.Text = BarCodeText
    barCode.Width = 400
    barCode.Height = 150

    ' If the AutoModule property is set to false, uncomment the next line.
    barCode.AutoModule = True
    'barcode.Module = 3;

    ' Adjust the properties specific to the barcode type.
    CType(barCode.Symbology, DataMatrixGenerator).CompactionMode = DataMatrixCompactionMode.Text
    CType(barCode.Symbology, DataMatrixGenerator).MatrixSize = DataMatrixSize.MatrixAuto

    Return barCode
End Function