FieldMergingArgsBase.DocumentFieldName property

Gets the name of the merge field as specified in the document.

public string DocumentFieldName { get; }


If you have a mapping from a document field name to a different data source field name, then this is the original field name as specified in the document.

If you specified a field name prefix, for example “Image:MyFieldName” in the document, then DocumentFieldName returns field name without the prefix, that is “MyFieldName”.


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