Use the code example below as a guideline for writing Data Matrix barcodes.

C# - Basic steps for barcode writing Data Matrix Barcodes using Accusoft.BarcodeXpress.Net

using (BarcodeXpress bx = new BarcodeXpress("."))
using (WriterDataMatrix dataMatrixWriter = new WriterDataMatrix(bx))
{
    // Set the text value
    dataMatrixWriter.BarcodeValue = "DataMatrix Value";

    using (Bitmap bitmap = dataMatrixWriter.CreateBitmap())
    {
        bitmap.Save("testfile.bmp");
    }
}

See Also

Try the Sample Applications