How to sum repeating merge field values during mail merge in a Word document?

Syncfusion® Essential® DocIO is a .NET Word library used to create, read, edit, and convert Word documents programmatically without Microsoft Word or interop dependencies. Using this library, you can sum repeating merge field values during mail merge in a Word document using C#.

Steps to sum repeating merge field values during mail merge in a Word document:

1. Create a new .NET Core console application project.
   
   
2. Install the Syncfusion.DocIO.Net.Core NuGet package as a reference to your project from NuGet.org.
   
   

3. Include the following namespaces in Program.cs file
   C#

using Syncfusion.DocIO.DLS;
using Syncfusion.DocIO; 

4. Use the following code example to store the total sum value.
   C#

static int totalMarks = 0;

5. Use the following code example to sum repeating merge field values during mail merge in a Word document.
   C#

using (FileStream fileStream = new FileStream(Path.GetFullPath(@"Data/Template.docx"), FileMode.Open))
{
   //Loads an existing Word document.
   using (WordDocument wordDocument = new WordDocument(fileStream, FormatType.Automatic))
   {
       // Gets JSON object from JSON string.
       JObject jsonObject = JObject.Parse(File.ReadAllText(Path.GetFullPath(@"Data/ReportData.json")));
       // Converts to IDictionary data from JSON object.
       IDictionary<string, object> data = GetData(jsonObject);
       //Creates the mail merge data table in order to perform mail merge
       MailMergeDataTable dataTable = new MailMergeDataTable("Reports", (List<object>)data["Reports"]);
       
       //Uses the mail merge event handler to sum the field's values and set that value to the TotalMarks field during mail merge.
       wordDocument.MailMerge.MergeField += new MergeFieldEventHandler(MergeField_Event);
       //Performs the mail merge operation with the dynamic collection
       wordDocument.MailMerge.ExecuteGroup(dataTable);

       string[] fieldNames = new string[] { "TotalMarks" };
       string[] fieldValues = new string[] { "" };
       //Performs the mail merge
       wordDocument.MailMerge.Execute(fieldNames, fieldValues);
       //Saves the WOrd document file to file system.    
       using (FileStream outputStream = new FileStream(Path.GetFullPath(@"Output/Result.docx"), FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite))
       {
           wordDocument.Save(outputStream, FormatType.Docx);
       }
   }
} 

6. Use the following code example to to sum the field’s values and set that value to the TotalMarks field during mail merge.
   C#

private static void MergeField_Event(object sender, MergeFieldEventArgs args)
{
    if (args.FieldName == "Marks")
    {
        //sum the Marks field values.
        totalMarks += Convert.ToInt32(args.FieldValue);
    }
    if (args.FieldName == "TotalMarks")
    {
        //Set sum of the Marks field values to the TotalMarks field;
        args.Text = totalMarks.ToString();
    }
}

7. Use the following code example to get array of items from JSON array.
   C#

private static List<object> GetData(JArray jArray)
{
    List<object> jArrayItems = new List<object>();
    foreach (var item in jArray)
    {
        object keyValue = null;
        if (item is JObject)
            keyValue = GetData((JObject)item);
        jArrayItems.Add(keyValue);
    }
    return jArrayItems;
}

8. Use the following code example to get data from JSON object.
   C#

private static IDictionary<string, object> GetData(JObject jsonObject)
{
    Dictionary<string, object> dictionary = new Dictionary<string, object>();
    foreach (var item in jsonObject)
    {
        object keyValue = null;
        if (item.Value is JArray)
            keyValue = GetData((JArray)item.Value);
        else if (item.Value is JToken)
            keyValue = ((JToken)item.Value).ToObject<string>();
        dictionary.Add(item.Key, keyValue);
    }
    return dictionary;
} 

You can download a complete working sample to sum repeating merge field values during mail merge in a Word document from the GitHub.

Take a moment to peruse the documentation where you can find basic Word document processing options along with the features like mail merge, merge, split, and compare Word documents, find and replace text in the Word document, protect the Word documents, and most importantly, the PDF and Image conversions with code examples.

Conclusion

I hope you enjoyed learning about how to sum repeating merge field values during mail merge in a Word document in .NET Core Word document.

You can refer to our ASP.NET Core DocIO feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our ASP.NET Core DocIO example to understand how to create and manipulate data.

For current customers, you can check out our components from the License and Downloads page. If you are new to Syncfusion®, you can try our 30-day free trial to check out our other controls.

If you have any queries or require clarifications, please let us know in the comments section below. You can also contact us through our support forums, Direct-Trac, or feedback portal. We are always happy to assist you!