# Mail Merge with HTML Formatted Strings in RadWordsProcessing

## Environment

| Version    | Product            | Author                                                                |
| ---------- | ------------------ | --------------------------------------------------------------------- |
| 2026.1.210 | RadWordsProcessing | [Yoan Karamanov](https://www.telerik.com/blogs/author/yoan-karamanov) |

## Description

When you perform a [Mail Merge](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/editing/mail-merge) operation with a DOCX template, the merge data may include HTML formatted strings. By default, the library does not parse these HTML strings and displays them 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:**

![Unparsed HTML Result](https://www.telerik.com/document-processing-libraries/documentation/assets/de5bd820f15f246c68306589f3b73e02/mail-merge-html-unparsed.png)

**With HTML Parsing:**

![Parsed HTML Result](https://www.telerik.com/document-processing-libraries/documentation/assets/4ee8f2e0bcba14abb847986dd4a14307/mail-merge-html-result.png)

## Solution

The solution involves importing the HTML formatted strings as separate [RadFlowDocument](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/model/radflowdocument) instances with the [HtmlFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/formats-and-conversion/html/htmlformatprovider), then replacing the original HTML text with the parsed content.

The following example shows the complete workflow:

* Import the template document with [DocxFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/formats-and-conversion/word-file-formats/docx/docxformatprovider)
* Perform the mail merge operation with data that contains HTML strings
* Iterate through all table cells in the merged document
* Detect lines that contain HTML tags (use regex to find "<" or ">")
* Import each HTML string as a separate document with [HtmlFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/formats-and-conversion/html/htmlformatprovider)
* Replace the raw HTML text with the parsed content with [RadFlowDocumentEditor](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/editing/radflowdocumenteditor)
* Export the final document

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

### Empty Template Document

![Empty Template Document](https://www.telerik.com/document-processing-libraries/documentation/assets/4db0edda7a47f90caa4729248cb8356d/mail-merge-html-template.png)

### **Example 1: 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](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/editing/mail-merge)
* [RadFlowDocument](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/model/radflowdocument)
* [RadFlowDocumentEditor](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/editing/radflowdocumenteditor)
* [HtmlFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/formats-and-conversion/html/htmlformatprovider)
* [Find and Replace Text and Style](https://www.telerik.com/document-processing-libraries/documentation/libraries/radwordsprocessing/editing/find-and-replace/find-and-replace-text)