Mail Merge with HTML Formatted Strings in RadWordsProcessing

Updated on Feb 19, 2026

Environment

Version	Product	Author
2026.1.210	RadWordsProcessing	Yoan Karamanov

Description

When performing a Mail Merge operation with a DOCX template, the merge data may include HTML formatted strings. By default, these HTML strings are not parsed and are displayed as raw text in the result document after the mail merge. However, you can process and parse these HTML strings to display them with their intended formatting in the final document.

Without HTML Parsing:

With HTML Parsing:

Solution

The solution involves importing the HTML formatted strings as separate RadFlowDocument instances using the HtmlFormatProvider, then replacing the original HTML text with the parsed content.

The following example demonstrates the complete workflow:

• Import the template document using DocxFormatProvider
• Perform the mail merge operation with data containing HTML strings
• Iterate through all table cells in the merged document
• Detect lines containing HTML tags (using regex to find "<" or ">")
• Import each HTML string as a separate document using HtmlFormatProvider
• Replace the raw HTML text with the parsed content using RadFlowDocumentEditor
• Export the final document

The implementation can vary depending on the template document structure and the HTML content.

Empty Template Document

Mail Merge with HTML Formatted Strings

csharp

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using Telerik.Windows.Documents.Flow.FormatProviders.Docx;
using Telerik.Windows.Documents.Flow.FormatProviders.Html;
using Telerik.Windows.Documents.Flow.Model;
using Telerik.Windows.Documents.Flow.Model.Editing;

var mergeData = new List<Incident>{
    new Incident{
        ReportNumber = "INC-2024-004",
        People = new List<Person>{
            new Person{
                FirstName = "<p>Michael</p></br><p>John<p>",
                LastName = "<u>Williams</u>",
                Phones = new List<Phone>{
                    new Phone{ PhoneNumber = "<b>213-555-0401</b>" },
                    new Phone{ PhoneNumber = "<b>213-555-0402</b>" },
                    new Phone{ PhoneNumber = "<b>213-555-0403</b>" }
                }
            },
            new Person{
                FirstName = "<i>Sarah</i>",
                LastName = "<u>Williams</u>",
                Phones = new List<Phone>{
                    new Phone{ PhoneNumber = "213-555-0404" }
                }
            }
        }
    },
    new Incident{
        ReportNumber = "INC-2024-005",
        People = new List<Person>{
            new Person{
                FirstName = "<b>David</b>",
                LastName = "<u>Brown</u>",
                Phones = new List<Phone>{
                    new Phone{ PhoneNumber = "<s>818-555-0501</s>" },
                    new Phone{ PhoneNumber = "<s>818-555-0502</s>" }
                }
            },
            new Person{
                FirstName = "<i>Emily</i>",
                LastName = "<u>Davis</u>",
                Phones = new List<Phone>{
                    new Phone{ PhoneNumber = "<b>818-555-0503</b>" }
                }
            },
            new Person{
                FirstName = "<i>Christopher</i>",
                LastName = "<u>Martinez</u>",
                Phones = new List<Phone>{
                    new Phone{ PhoneNumber = "<b>818-555-0504</b>" }
                }
            }
        }
    }
};

RadFlowDocument template;
DocxFormatProvider docxFormatProvider = new DocxFormatProvider();

using (Stream input = File.OpenRead("template.docx"))
{
    template = docxFormatProvider.Import(input, null);
}

RadFlowDocument mailMergeResult = template.MailMerge(mergeData);
RadFlowDocumentEditor htmlEditor = new RadFlowDocumentEditor(mailMergeResult);
var tables = mailMergeResult.EnumerateChildrenOfType<Table>();

var regex = new Regex(@"[<>]");

HtmlFormatProvider htmlFormatProvider = new HtmlFormatProvider();

// Iterate all table lines of text
foreach (Table table in tables)
{
    foreach (TableRow row in table.Rows)
    {
        foreach (TableCell cell in row.Cells)
        {
            foreach (var block in cell.Blocks.ToList())
            {
                var paragraph = block as Paragraph;

                if (paragraph != null)
                {
                    foreach (var inline in paragraph.Inlines.ToList())
                    {
                        string line = inline.ToString();

                        // If line contains "<" or ">", treat it as HTML and import it as an HTML document
                        if (regex.IsMatch(line))
                        {
                            RadFlowDocument htmlDocument = htmlFormatProvider.Import(line, TimeSpan.FromSeconds(10));

                            // Clear the paragraph of the original line and insert the new fomatted HTML document
                            paragraph.Inlines.Clear();
                            htmlEditor.MoveToParagraphEnd(paragraph);
                            htmlEditor.InsertDocument(htmlDocument);
                        }
                    }
                }
            }
        }
    }
}

string docxOutputPath = "output.docx";
using (Stream output = File.OpenWrite(docxOutputPath))
{
    docxFormatProvider.Export(mailMergeResult, output, TimeSpan.FromSeconds(20));
}

var psi = new ProcessStartInfo()
{
    FileName = docxOutputPath,
    UseShellExecute = true
};
Process.Start(psi);

public class Incident
{
    public string ReportNumber { get; set; }
    public List<Person> People { get; set; }
}

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public List<Phone> Phones { get; set; }
}

public class Phone
{
    public string PhoneNumber { get; set; }
}

See Also

• Mail Merge
• RadFlowDocument
• RadFlowDocumentEditor
• HtmlFormatProvider
• Find and Replace Text and Style