Word Processing Document API - How to Automate Mail Merge: Generate, Populate, and Export Documents

C#
using DevExpress.Office.Services;
using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;
using System.Data;
using System.Diagnostics;

namespace WordProcessingMailMerge
{
    internal class Program
    {
        static void Main(string[] args)
        {
            DataSet xmlDataSet = new DataSet();
            xmlDataSet.ReadXml("..\\..\\..\\Employees.xml");
            xmlDataSet.Tables[0].PrimaryKey = new DataColumn[] { xmlDataSet.Tables[0].Columns[0] };

            using (var wordProcessor = new RichEditDocumentServer())
            {
                wordProcessor.LoadDocument("..\\..\\..\\template.docx");
                AddMailMergeFields(wordProcessor.Document);
                wordProcessor.CalculateDocumentVariable += WordProcessor_CalculateDocumentVariable;

                // Register the URI provider service
                IUriStreamService uriStreamService = wordProcessor.GetService<IUriStreamService>();
                uriStreamService.RegisterProvider(new ImageStreamProvider(xmlDataSet.Tables[0], "Photo"));

                MailMergeOptions myMergeOptions =
                    wordProcessor.Document.CreateMailMergeOptions();
                myMergeOptions.DataSource = xmlDataSet.Tables[0];
                myMergeOptions.MergeMode = MergeMode.NewSection;

                wordProcessor.MailMerge(myMergeOptions, "result.docx", DocumentFormat.OpenXml);
            }

            Process.Start(new ProcessStartInfo("result.docx") { UseShellExecute = true });
        }
        private static void AddMailMergeFields(Document document)
        {
            DocumentRange[] pictureRanges = document.FindAll("Photo", SearchOptions.WholeWord);

            foreach (var pictureRange in pictureRanges)
            {
                DocumentPosition picturePosition = pictureRange.End;

                // Delete the placeholder
                document.Delete(pictureRange);

                // Insert a field to a picture from a database
                Field pictureField = document.Fields.Create(picturePosition, @"INCLUDEPICTURE ""dbimg://{ placeholder }""");

                // Find a placeholder for a nested MERGEFIELD
                DocumentRange nestedFieldRange =
                    document.FindAll("{ placeholder }", SearchOptions.WholeWord, pictureField.CodeRange).First();

                // Clear the placeholder range
                document.Delete(nestedFieldRange);

                // Create a nested field
                document.Fields.Create(nestedFieldRange.Start, "MERGEFIELD EmployeeID");
            }

            // Find a placeholder for another image
            // in the footer
            SubDocument footer = document.Sections[0].BeginUpdateFooter();
            DocumentRange[] imageRanges =
                footer.FindAll("image", SearchOptions.WholeWord);
            foreach (var imageRange in imageRanges)
            {
                DocumentPosition imagePosition = imageRange.End;

                // Delete the phrase
                footer.Delete(imageRange);

                // Create a field at the placeholder's position
                footer.Fields.Create(imagePosition, @"INCLUDEPICTURE ""DevExpress.png""");
            }
            footer.EndUpdate();

            // Find a placeholder for the FirstName field:
            DocumentRange[] nameRanges =
                document.FindAll("FirstName", SearchOptions.WholeWord);
            foreach (var nameRange in nameRanges)
            {
                DocumentPosition namePosition = nameRange.End;

                // Delete the phrase
                document.Delete(nameRange);

                // Create a field at the placeholder position
                document.Fields.Create(namePosition, @"MERGEFIELD ""FirstName""");
            }
        }
        private static void WordProcessor_CalculateDocumentVariable(object sender, CalculateDocumentVariableEventArgs e)
        {
            if (e.Arguments.Count > 0)
            {
                // Retrieve the MERGEFIELD field value
                DateTimeOffset hireDate = Convert.ToDateTime(e.Arguments[0].Value);
                DateTimeOffset currentDate = DateTime.Now;

                // Calculate the difference between the current date
                // and the hire date
                var dif = currentDate.Subtract(hireDate);

                // Calculate the number of years
                int years = dif.Days / 365;

                // Specify the DOCVARIABLE field value
                e.Value = years.ToString();
                e.Handled = true;
            }
            e.Handled = true;
        }
    }
}

Visual Basic
Option Infer On

Imports DevExpress.Office.Services
Imports DevExpress.XtraRichEdit
Imports DevExpress.XtraRichEdit.API.Native
Imports System.Data
Imports System.Diagnostics

Namespace WordProcessingMailMerge
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            Dim xmlDataSet As New DataSet()
            xmlDataSet.ReadXml("..\..\..\Employees.xml")
            xmlDataSet.Tables(0).PrimaryKey = New DataColumn() { xmlDataSet.Tables(0).Columns(0) }

            Using wordProcessor = New RichEditDocumentServer()
                wordProcessor.LoadDocument("..\..\..\template.docx")
                AddMailMergeFields(wordProcessor.Document)
                AddHandler wordProcessor.CalculateDocumentVariable, AddressOf WordProcessor_CalculateDocumentVariable

                ' Register the URI provider service
                Dim uriStreamService As IUriStreamService = wordProcessor.GetService(Of IUriStreamService)()
                uriStreamService.RegisterProvider(New ImageStreamProvider(xmlDataSet.Tables(0), "Photo"))

                Dim myMergeOptions As MailMergeOptions = wordProcessor.Document.CreateMailMergeOptions()
                myMergeOptions.DataSource = xmlDataSet.Tables(0)
                myMergeOptions.MergeMode = MergeMode.NewSection

                wordProcessor.MailMerge(myMergeOptions, "result.docx", DocumentFormat.OpenXml)
            End Using

            Process.Start(New ProcessStartInfo("result.docx") With {.UseShellExecute = True})
        End Sub
        Private Shared Sub AddMailMergeFields(ByVal document As Document)
            Dim pictureRanges() As DocumentRange = document.FindAll("Photo", SearchOptions.WholeWord)

            For Each pictureRange In pictureRanges
                Dim picturePosition As DocumentPosition = pictureRange.End

                ' Delete the placeholder
                document.Delete(pictureRange)

                ' Insert a field to a picture from a database
                Dim pictureField As Field = document.Fields.Create(picturePosition, "INCLUDEPICTURE ""dbimg://{ placeholder }""")

                ' Find a placeholder for a nested MERGEFIELD
                Dim nestedFieldRange As DocumentRange = document.FindAll("{ placeholder }", SearchOptions.WholeWord, pictureField.CodeRange).First()

                ' Clear the placeholder range
                document.Delete(nestedFieldRange)

                ' Create a nested field
                document.Fields.Create(nestedFieldRange.Start, "MERGEFIELD EmployeeID")
            Next pictureRange

            ' Find a placeholder for another image
            ' in the footer
            Dim footer As SubDocument = document.Sections(0).BeginUpdateFooter()
            Dim imageRanges() As DocumentRange = footer.FindAll("image", SearchOptions.WholeWord)
            For Each imageRange In imageRanges
                Dim imagePosition As DocumentPosition = imageRange.End

                ' Delete the phrase
                footer.Delete(imageRange)

                ' Create a field at the placeholder's position
                footer.Fields.Create(imagePosition, "INCLUDEPICTURE ""DevExpress.png""")
            Next imageRange
            footer.EndUpdate()

            ' Find a placeholder for the FirstName field:
            Dim nameRanges() As DocumentRange = document.FindAll("FirstName", SearchOptions.WholeWord)
            For Each nameRange In nameRanges
                Dim namePosition As DocumentPosition = nameRange.End

                ' Delete the phrase
                document.Delete(nameRange)

                ' Create a field at the placeholder position
                document.Fields.Create(namePosition, "MERGEFIELD ""FirstName""")
            Next nameRange
        End Sub
        Private Shared Sub WordProcessor_CalculateDocumentVariable(ByVal sender As Object, ByVal e As CalculateDocumentVariableEventArgs)
            If e.Arguments.Count > 0 Then
                ' Retrieve the MERGEFIELD field value
                Dim hireDate As DateTimeOffset = Convert.ToDateTime(e.Arguments(0).Value)
                Dim currentDate As DateTimeOffset = Date.Now

                ' Calculate the difference between the current date
                ' and the hire date
                Dim dif = currentDate.Subtract(hireDate)

                ' Calculate the number of years
                Dim years As Integer = dif.Days \ 365

                ' Specify the DOCVARIABLE field value
                e.Value = years.ToString()
                e.Handled = True
            End If
            e.Handled = True
        End Sub
    End Class
End Namespace

C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WordProcessingMailMerge
{
    using DevExpress.Office.Services;
    using System;
    using System.Data;
    using System.IO;

    public class ImageStreamProvider : IUriStreamProvider
    {
        static readonly string prefix = "dbimg://";
        DataTable table;
        string columnName;

        public ImageStreamProvider(DataTable sourceTable, string imageColumn)
        {
            this.table = sourceTable;
            this.columnName = imageColumn;
        }


        public Stream GetStream(string uri)
        {
            // Parse the retrieved URI string
            uri = uri.Trim();
            if (!uri.StartsWith(prefix))
                return null;

            // Remove the prefix from the retrieved URI string
            string strId = uri.Substring(prefix.Length).Trim();
            int id;

            // Check if the string contains the primary key
            if (!int.TryParse(strId, out id))
                return null;

            // Retrieve the row that corresponds
            // with the key
            DataRow row = table.Rows.Find(id);
            if (row == null)
                return null;

            // Convert the image string from this row
            // to a byte array
            byte[] bytes = Convert.FromBase64String(row[columnName] as string) as byte[];
            if (bytes == null)
                return null;

            // Return the MemoryStream with an image
            MemoryStream memoryStream = new MemoryStream(bytes);
            return memoryStream;
        }
    }
}

Visual Basic
Imports System.IO
Imports System.Data
Imports DevExpress.Office.Services
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks

Namespace WordProcessingMailMerge

    Public Class ImageStreamProvider
        Implements IUriStreamProvider

        Private Shared ReadOnly prefix As String = "dbimg://"
        Private table As DataTable
        Private columnName As String

        Public Sub New(ByVal sourceTable As DataTable, ByVal imageColumn As String)
            Me.table = sourceTable
            Me.columnName = imageColumn
        End Sub


        Public Function GetStream(ByVal uri As String) As Stream Implements IUriStreamProvider.GetStream
            ' Parse the retrieved URI string
            uri = uri.Trim()
            If Not uri.StartsWith(prefix) Then
                Return Nothing
            End If

            ' Remove the prefix from the retrieved URI string
            Dim strId As String = uri.Substring(prefix.Length).Trim()
            Dim id As Integer = Nothing

            ' Check if the string contains the primary key
            If Not Integer.TryParse(strId, id) Then
                Return Nothing
            End If

            ' Retrieve the row that corresponds
            ' with the key
            Dim row As DataRow = table.Rows.Find(id)
            If row Is Nothing Then
                Return Nothing
            End If

            ' Convert the image string from this row
            ' to a byte array
            Dim bytes() As Byte = TryCast(Convert.FromBase64String(TryCast(row(columnName), String)), Byte())
            If bytes Is Nothing Then
                Return Nothing
            End If

            ' Return the MemoryStream with an image
            Dim memoryStream As New MemoryStream(bytes)
            Return memoryStream
        End Function
    End Class
End Namespace