FieldMergingArgs.Text property

Gets or sets the text that will be inserted into the document for the current merge field.

public string Text { get; set; }


When your event handler is called, this property is set to null.

If you leave Text as null, the mail merge engine will insert FieldValue in place of the merge field.

If you set Text to any string (including empty), the string will be inserted into the document in place of the merge field.


Shows how to execute a mail merge with a custom callback that handles merge data in the form of HTML documents.

    Document doc = new Document();
    DocumentBuilder builder = new DocumentBuilder(doc);

    builder.InsertField(@"MERGEFIELD  html_Title  \b Content");
    builder.InsertField(@"MERGEFIELD  html_Body  \b Content");

    object[] mergeData =
        "<html>" +
            "<h1>" +
                "<span style=\"color: #0000ff; font-family: Arial;\">Hello World!</span>" +
            "</h1>" +

        "<html>" +
            "<blockquote>" +
                "<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>" +
            "</blockquote>" +

    doc.MailMerge.FieldMergingCallback = new HandleMergeFieldInsertHtml();
    doc.MailMerge.Execute(new[] { "html_Title", "html_Body" }, mergeData);

    doc.Save(ArtifactsDir + "MailMergeEvent.MergeHtml.docx");

/// <summary>
/// If the mail merge encounters a MERGEFIELD whose name starts with the "html_" prefix,
/// this callback parses its merge data as HTML content and adds the result to the document location of the MERGEFIELD.
/// </summary>
private class HandleMergeFieldInsertHtml : IFieldMergingCallback
    /// <summary>
    /// Called when a mail merge merges data into a MERGEFIELD.
    /// </summary>
    void IFieldMergingCallback.FieldMerging(FieldMergingArgs args)
        if (args.DocumentFieldName.StartsWith("html_") && args.Field.GetFieldCode().Contains("\\b"))
            // Add parsed HTML data to the document's body.
            DocumentBuilder builder = new DocumentBuilder(args.Document);

            // Since we have already inserted the merged content manually,
            // we will not need to respond to this event by returning content via the "Text" property. 
            args.Text = string.Empty;

    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs args)
        // Do nothing.

See Also