You can use progress bars to indicate the upload or download progress.

For the complete code of progress bars, see GitHub.

The following code is used as an example to describe how to view progress information with PutObject:

using System;
using System.IO;
using System.Text;
using Aliyun.OSS;
using Aliyun.OSS.Common;
namespace PutObjectProgress
{
    class Program
    {
        static void Main(string[] args)
        {
            Program.PutObjectProgress();
            Console.ReadKey();
        }
        public static void PutObjectProgress()
        {
            var endpoint = "<yourEndpoint>";
            var accessKeyId = "<yourAccessKeyId>";
            var accessKeySecret = "<yourAccessKeySecret>";
            var bucketName = "<yourBucketName>";
            var objectName = "<yourObjectName>";
            var localFilename = "<yourLocalFilename>";
            // Create an OSSClient instance.
            var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
            // Upload with a progress bar displayed.
            try
            {
                using (var fs = File.Open(localFilename, FileMode.Open))
                {
                    var putObjectRequest = new PutObjectRequest(bucketName, objectName, fs);
                    putObjectRequest.StreamTransferProgress += streamProgressCallback;
                    client.PutObject(putObjectRequest);
                }
                Console.WriteLine("Put object:{0} succeeded", objectName);
            }
            catch (OssException ex)
            {
                Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID: {2}\tHostID: {3}",
                    ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed with error info: {0}", ex.Message);
            }
        }
        // Obtain the upload progress.
        private static void streamProgressCallback(object sender, StreamTransferProgressArgs args)
        {
            System.Console.WriteLine("ProgressCallback - Progress: {0}%, TotalBytes:{1}, TransferredBytes:{2} ",
                args.TransferredBytes * 100 / args.TotalBytes, args.TotalBytes, args.TransferredBytes);
        }
    }
}