PDF-Rechnungsgenerator in .NET erstellen

Häufig kommt es vor, dass Rechnungen im PDF-Format erstellt werden müssen. Normalerweise enthält das Rechnungsdokument ein komplexes Layout: eine Kopfzeile mit Logo und Firmeninformationen, Informationen zum Verkäufer und Käufer, eine Tabelle mit den bestellten Artikeln und eine Fußzeile mit zusätzlichen Informationen.

Ein PDF-Dokument ist ein Vektordokument und bietet daher keine Funktionen für das Inhaltslayout. Es ist zwar möglich, Programmcode zu schreiben, der die Dokumentauszeichnung mithilfe von Vektorgrafiken auf der PDF-Seite darstellt, doch wäre dieser Code komplex und seine Entwicklung zeitaufwendig.

Eine komplexe Aufgabe ließe sich vereinfachen, indem man sie in zwei Teile aufteilt:
1. Erstellen einer Dokumentvorlage im Texteditor.
2. Schreiben des Programmcodes, der die Vorlage mit dynamischen Daten füllt.

DOCX-Dokumente speichern Inhalte in Form von Markup und können daher verwendet werden, um eine Vorlage für Rechnungen beliebiger Komplexität zu erstellen.
Seit Version 10.1 des VintaSoft Imaging .NET SDK ist es möglich, bestehende DOCX- und XLSX-Dokumente programmatisch zu bearbeiten.
Mit dieser Funktion kann ein einfacher und leicht anpassbarer Generator für Rechnungen im PDF-Dokumentformat erstellt werden.

Der Rechnungsgenerator sollte zwei Hauptteile enthalten:

• die Rechnungsvorlage im DOCX-Dokumentformat mit statischem Markup der Rechnung,
• der Anwendungscode, der die dynamischen Daten in die Rechnungsvorlage einfügt und die Rechnung als PDF-Dokument speichert.

Die Vorteile der Erstellung eines Rechnungsgenerators auf Basis einer DOCX-Dokumentvorlage sind:

• Die Änderung des statischen Layouts der Rechnung ist sehr einfach; dazu genügt es, die Vorlage mit MS Word zu ändern
• die Einfachheit des Anwendungscodes, da die Anwendung lediglich die Daten einfügt.

Weitere Details zur programmatischen Bearbeitung von DOCX-Dokumenten finden Sie hier.


Um den Rechnungsgenerator zu erstellen, der die Rechnung im PDF-Dokumentformat generiert, sind folgende Schritte erforderlich:
1. Erstellen Sie mit MS Word eine Rechnungsvorlage namens "Invoice_template.docx", die die gesamte statische Formatierung der Rechnung enthält.
2. Implementieren Sie in der Anwendung das Befüllen von Rechnungen mit dynamischen Daten mithilfe der Klasse DocxDocumentEditor.

Hier ist der Code, der zeigt, wie eine Rechnung erstellt und als PDF-Dokument gespeichert wird:

• Rechnungsvorlage: Rechnungsvorlage.docx
• Generierte Rechnung: Rechnung.pdf

// The project, which uses this code, must have references to the following assemblies:
// - Vintasoft.Imaging
// - Vintasoft.Imaging.Office.OpenXml
// - Vintasoft.Imaging.Pdf
// - Vintasoft.Barcode

/// <summary>
/// Generates invoice, which is based on DOCX document template.
/// </summary>
public static void GenerateInvoiceUsingDocxTemplate()
{
    // create DOCX document editor and use file "Invoice_template.docx" as document template
    using (Vintasoft.Imaging.Office.OpenXml.Editor.DocxDocumentEditor editor =
        new Vintasoft.Imaging.Office.OpenXml.Editor.DocxDocumentEditor("Invoice_template.docx"))
    {
        // generate test invoice data with 30 items
        InvoiceData testData = GetTestData(30);

        // fill invoice data
        FillInvoiceData(editor, testData);

        // save invoice to a DOCX document if necessary
        //editor.Save("Invoice.docx");

        // export invoice to a PDF document
        editor.Export("Invoice_docx.pdf");
    }
}

/// <summary>
/// Fills the invoice data using DOCX document editor.
/// </summary>
/// <param name="documentEditor">The DOCX document editor.</param>
/// <param name="invoiceData">The invoice data.</param>
private static void FillInvoiceData(
    Vintasoft.Imaging.Office.OpenXml.Editor.DocxDocumentEditor documentEditor,
    InvoiceData invoiceData)
{
    // create QR code image 200x200 px
    using (Vintasoft.Imaging.VintasoftImage qrCodeImage = invoiceData.GetBarcodeImage(200))
    {
        // set barcode image to the image element at index 1
        documentEditor.Images[1].SetImage(qrCodeImage);
    }

    // fill the document header
    documentEditor.Body["[company_name]"] = invoiceData.Company.CompanyName;
    documentEditor.Body["[company_address]"] = invoiceData.Company.Address;
    documentEditor.Body["[company_city]"] = invoiceData.Company.City;
    documentEditor.Body["[company_phone]"] = invoiceData.Company.GetPhones();
    documentEditor.Body["[invoice_number]"] = invoiceData.InvoiceNumber;
    documentEditor.Body["[invoice_date]"] = System.DateTime.Now.ToShortDateString();

    // get all tables of document
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable[] tables = documentEditor.Tables;

    // fill the "Customer Information" table
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable customerInformationTable = tables[0];
    SetCompanyInformation(customerInformationTable, "billing", invoiceData.BillingAddress);
    SetCompanyInformation(customerInformationTable, "shipping", invoiceData.ShippingAddress);

    // fill the "Shipping Method" table
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable shippingMethodTable = tables[1];
    shippingMethodTable["[shipping_method]"] = invoiceData.ShippingMethod;

    // fill the "Order Information" table
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable orderInformationTable = tables[2];
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTableRow templateRow = orderInformationTable[1];
    int orderItemNumber = 1;
    // for each item in invoice
    foreach (InvoiceItem orderItem in invoiceData.OrderItems)
    {
        // copy template row and insert copy after template row
        Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTableRow currentRow = templateRow;
        templateRow = (Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTableRow)templateRow.InsertCopyAfterSelf();

        // fill data of current row
        currentRow["[p_n]"] = orderItemNumber.ToString();
        currentRow["[p_description]"] = orderItem.Product;
        currentRow["[p_qty]"] = orderItem.Quantity.ToString();
        currentRow["[p_unit_price]"] = invoiceData.GetPriceAsString(orderItem.Price);
        currentRow["[p_price_total]"] = invoiceData.GetPriceAsString(orderItem.TotalPrice);

        orderItemNumber++;
    }
    // remove template row
    templateRow.Remove();

    // fill order information summary fields
    orderInformationTable["[subtotal]"] = invoiceData.GetPriceAsString(invoiceData.Subtotal);
    orderInformationTable["[tax]"] = invoiceData.GetPriceAsString(invoiceData.Tax);
    orderInformationTable["[shipping]"] = invoiceData.GetPriceAsString(invoiceData.Shipping);
    orderInformationTable["[grand_total]"] = invoiceData.GetPriceAsString(invoiceData.GrandTotal);

    // fill the "Notes" table
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable notesTable = tables[3];
    notesTable["[date]"] = System.DateTime.Now.ToShortDateString();
    notesTable["[time]"] = System.DateTime.Now.ToLongTimeString();
}

/// <summary>
/// Sets the company information.
/// </summary>
/// <param name="table">The table.</param>
/// <param name="fieldName">Name of the field.</param>
/// <param name="company">The company.</param>
private static void SetCompanyInformation(
    Vintasoft.Imaging.Office.OpenXml.Editor.OpenXmlDocumentTable table, 
    string fieldName, 
    Company company)
{
    string fieldFormat = string.Format("[{0}_{1}]", fieldName, "{0}");
    table[string.Format(fieldFormat, "company")] = company.CompanyName;
    table[string.Format(fieldFormat, "name")] = company.Name;
    table[string.Format(fieldFormat, "address")] = company.Address;
    table[string.Format(fieldFormat, "phone")] = company.GetPhones();
    table[string.Format(fieldFormat, "city")] = company.City;
}

Der folgende Code erstellt die Testdaten für den Rechnungsgenerator:

/// <summary>
/// Returns the invoice test data.
/// </summary>
/// <returns>The invoice test data.</returns>
public static InvoiceData GetTestData(int orderItemsCount)
{
    Company vintasoftCompany = new Company();
    vintasoftCompany.CompanyName = "VintaSoft LLC";

    Company billingCompany = new Company();
    billingCompany.CompanyName = "Billing Global Company Inc.";
    billingCompany.Name = "Mr. Q";
    billingCompany.Address = "Address1";
    billingCompany.City = "City1";
    billingCompany.Phones.Add("9876543210");
    billingCompany.Phones.Add("7654321098 (fax)");

    Company shipingCompany = new Company();
    shipingCompany.CompanyName = "Shipping Global Company Inc.";
    shipingCompany.Name = "Mr. Z";
    shipingCompany.Address = "Address2";
    shipingCompany.City = "City2";
    shipingCompany.Phones.Add("1122334455");
    shipingCompany.Phones.Add("5544332211 (fax)");

    InvoiceData data = new InvoiceData();

    System.Random random = new System.Random();
    data.InvoiceNumber = string.Format("{0}-{1}", random.Next(100000, 999999), random.Next(0, 9));

    data.Company = vintasoftCompany;
    data.BillingAddress = billingCompany;
    data.ShippingAddress = shipingCompany;

    InvoiceItem[] availableProducts = new InvoiceItem[] {
        new InvoiceItem("VintaSoft Imaging .NET SDK, Site license for Desktop PCs", 659.95f),
        new InvoiceItem("VintaSoft Annotation .NET Plug-in, Site license for Desktop PCs", 449.95f),
        new InvoiceItem("VintaSoft Office .NET Plug-in, Site license for Desktop PCs", 569.95f),
        new InvoiceItem("VintaSoft PDF .NET Plug-in (Reader+Writer), Site license for Desktop PCs", 1499.95f),
        new InvoiceItem("VintaSoft PDF .NET Plug-in (Reader+Writer+VisualEditor), Site license for Desktop PCs", 2999.95f),
        new InvoiceItem("VintaSoft JBIG2 .NET Plug-in, Site license for Desktop PCs", 1139.95f),
        new InvoiceItem("VintaSoft JPEG2000 .NET Plug-in, Site license for Desktop PCs", 689.95f),
        new InvoiceItem("VintaSoft Document Cleaup .NET Plug-in, Site license for Desktop PCs", 569.95f),
        new InvoiceItem("VintaSoft OCR .NET Plug-in, Site license for Desktop PCs", 509.95f),
        new InvoiceItem("VintaSoft DICOM .NET Plug-in (Codec+MPR), Site license for Desktop PCs", 1199.95f),
        new InvoiceItem("VintaSoft Forms Processing .NET Plug-in, Site license for Desktop PCs", 509.95f),
        new InvoiceItem("VintaSoft Barcode .NET SDK (1D+2D Reader+Writer), Site license for Desktop PCs", 1379.95f),
        new InvoiceItem("VintaSoft Twain .NET SDK, Site license", 539.95f)
    };

    for (int i = 0; i < orderItemsCount; i++)
    {
        int quantity = 1 + random.Next(10);
        int index = random.Next(availableProducts.Length - 1);
        data.OrderItems.Add(new InvoiceItem(availableProducts[index], quantity));
    }

    return data;
}

/// <summary>
/// Represents an information about company.
/// </summary>
public class Company
{

    /// <summary>
    /// The company name.
    /// </summary>
    public string CompanyName;

    /// <summary>
    /// The person name.
    /// </summary>
    public string Name;

    /// <summary>
    /// The company location city.
    /// </summary>
    public string City;

    /// <summary>
    /// The company location adress.
    /// </summary>
    public string Address;

    /// <summary>
    /// The company phone numbers.
    /// </summary>
    public System.Collections.Generic.List<string> Phones = new System.Collections.Generic.List<string>();



    /// <summary>
    /// Returns the phone numbers.
    /// </summary>
    public string GetPhones()
    {
        if (Phones.Count == 1)
            return Phones[0];
        System.Text.StringBuilder result = new System.Text.StringBuilder();
        for (int i = 0; i < Phones.Count - 1; i++)
        {
            result.Append(Phones[i]);
            result.Append(", ");
        }
        result.Append(Phones[Phones.Count - 1]);
        return result.ToString();
    }

}

/// <summary>
/// Represents an invoice order item.
/// </summary>
public class InvoiceItem
{

    /// <summary>
    /// Initializes a new instance of the <see cref="InvoiceItem"/> class.
    /// </summary>
    /// <param name="product">The product name.</param>
    /// <param name="price">The product price.</param>
    public InvoiceItem(string product, float price)
    {
        Product = product;
        Quantity = 1;
        Price = price;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="InvoiceItem"/> class.
    /// </summary>
    /// <param name="source">The source <see cref="InvoiceItem"/>.</param>
    /// <param name="quantity">The product quantity.</param>
    public InvoiceItem(InvoiceItem source, float quantity)
    {
        Product = source.Product;
        Price = source.Price;
        Quantity = quantity;
    }



    /// <summary>
    /// The product name.
    /// </summary>
    public string Product;

    /// <summary>
    /// The product quantity.
    /// </summary>
    public float Quantity;

    /// <summary>
    /// The product price.
    /// </summary>
    public float Price;



    /// <summary>
    /// Gets the product total price.
    /// </summary>
    public float TotalPrice
    {
        get
        {
            return Price * Quantity;
        }
    }

}

/// <summary>
/// Represents an invoice data.
/// </summary>
public class InvoiceData
{

    /// <summary>
    /// The list of order items.
    /// </summary>
    public System.Collections.Generic.List<InvoiceItem> OrderItems = new System.Collections.Generic.List<InvoiceItem>();

    /// <summary>
    /// The invoice number.
    /// </summary>
    public string InvoiceNumber;

    /// <summary>
    /// The shipping method.
    /// </summary>
    public string ShippingMethod = "Email";

    /// <summary>
    /// The company billing address.
    /// </summary>
    public Company BillingAddress = new Company();

    /// <summary>
    /// The company shipping address.
    /// </summary>
    public Company ShippingAddress = new Company();

    /// <summary>
    /// The object that represents information about the company.
    /// </summary>
    public Company Company = new Company();

    /// <summary>
    /// The currency to be used in the invoice.
    /// </summary>
    public string Currency = "EUR";

    /// <summary>
    /// Gets or sets the tax value.
    /// </summary>
    public float Tax = 0;

    /// <summary>
    /// Gets or sets the shipping price.
    /// </summary>
    public float Shipping = 0;



    /// <summary>
    /// Gets the subtotal value.
    /// </summary>
    public float Subtotal
    {
        get
        {
            float value = 0;
            for (int i = 0; i < OrderItems.Count; i++)
                value += OrderItems[i].TotalPrice;
            return value;
        }
    }


    /// <summary>
    /// Gets the grandtotal value.
    /// </summary>
    public float GrandTotal
    {
        get
        {
            return Subtotal + Shipping + Tax;
        }
    }



    /// <summary>
    /// Returns the price as a string.
    /// </summary>
    /// <param name="price">The price.</param>
    /// <returns>The price in string representation.</returns>
    public string GetPriceAsString(float price)
    {
        return string.Format("{0} {1}", price.ToString("f2", System.Globalization.CultureInfo.InvariantCulture), Currency);
    }

    /// <summary>
    /// Creates the QR code image.
    /// </summary>
    /// <param name="size">The barcode size.</param>
    /// <returns>An instance o f<see cref="Vintasoft.Imaging.VintasoftImage"/> class that contains QR code image.</returns>
    public Vintasoft.Imaging.VintasoftImage GetBarcodeImage(int size)
    {
        Vintasoft.Barcode.BarcodeWriter writer = new Vintasoft.Barcode.BarcodeWriter();

        writer.Settings.Barcode = Vintasoft.Barcode.BarcodeType.QR;

        writer.Settings.Value = string.Format("INVOICE={0};TOTAL={1}", InvoiceNumber, GetPriceAsString(GrandTotal));

        writer.Settings.SetWidth(size);

        Vintasoft.Imaging.VintasoftImage result = 
            new Vintasoft.Imaging.VintasoftImage(writer.GetBarcodeAsBitmap(), true);
        result.Crop(new System.Drawing.Rectangle(0, 0, result.Width, result.Width));

        return result;
    }
}