#!c#

using System.IO;
using System.Text.RegularExpressions;
using DocumentFormat.OpenXml.Packaging;


// To search and replace content in a document part.
public static void SearchAndReplace(string document)
{
    using (WordprocessingDocument wordDoc = WordprocessingDocument.Open(document, true))
    {
        string docText = null;
        using (StreamReader sr = new StreamReader(wordDoc.MainDocumentPart.GetStream()))
        {
            docText = sr.ReadToEnd();
        }

        Regex regexText = new Regex("Hello world!");
        docText = regexText.Replace(docText, "Hi Everyone!");

        using (StreamWriter sw = new StreamWriter(wordDoc.MainDocumentPart.GetStream(FileMode.Create)))
        {
            sw.Write(docText);
        }
    }
}

#!c#

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Aspose.Words;

namespace TextManipulation
{
    class Program
    {
        static void Main(string[] args)
        {
            string projectFiles = Path.GetFullPath("../../Files/");

            Document doc = new Document(projectFiles + "TestDoc.docx");

            // Check the text of the document
            Console.WriteLine("Original document text: " + doc.Range.Text);

            // Replace the text in the document.
            doc.Range.Replace("_CustomerName_", "James Bond", false, false);

            // Check the replacement was made.
            Console.WriteLine("Document text after replace: " + doc.Range.Text);

            // Save the modified document.
            doc.Save(projectFiles + "ReplaceSimple Out.doc");

            System.Console.WriteLine("Press any key to continue");
            System.Console.ReadKey();

        }
    }
}