Using Valetude.Rollbar with

Rollbar.Windows.Forms.cs

using System;
using System.Windows.Forms;
using Valetude.Rollbar;

namespace MyCompany.Whatever
{
    internal static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        private static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            // The Following Three Lines of Code
            Application.ThreadException += new ThreadExceptionEventHandler(this.HandleUIException);
            Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);

            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(this.HandleException);

            Application.Run(new MyForm());
        }

        private static void HandleUIException(object sender, ThreadExceptionEventArgs t)
        {
          HandleException(a.Exception, sender, ErrorLevel.Error);
        }

        private static void HandleException(object sender, UnhandledExceptionEventArgs a)
        {
          HandleException(a.ExceptionObject, sender, a.IsTerminating ? ErrorLevel.Critical : ErrorLevel.Error);
        }
        
        private static void HandleException(Exception e, object sender, ErrorLevel level)
        {
          var payload = new RollbarPayload(MYGLOBAL_OR_INJECTED_ACCESS_TOKEN, new RollbarData("production", new RollbarBody(e)) { Level = level });
          var response = Rollbar.Send(payload);
          // You can inspect response for more info if desired
        }
    }
    
    public static class Rollbar {
        private const string RollbarApiEndpoint = "https://api.rollbar.com/api/1/item/";
        private const string ContentType = "application/json";

        public static RollbarResponse Send(RollbarPayload payload) {
            using (var client = new WebClient()) {
                client.Headers[HttpRequestHeader.ContentType] = ContentType;
                try {
                    return new RollbarResponse {
                        Message = client.UploadString(new Uri(RollbarApiEndpoint), "POST", payload.ToJson()),
                        StatusCode = RollbarResponseCode.Success,
                    };
                }
                catch (WebException exception) {
                    return new RollbarResponse {
                        Message = exception.Message,
                        StatusCode = ToRollbarStatus(exception.Status),
                    };
                }
            }
        }

        private static RollbarResponseCode ToRollbarStatus(WebExceptionStatus status) {
            switch ((int) status) {
                case 200:
                    return RollbarResponseCode.Success;
                case 400:
                    return RollbarResponseCode.BadRequest;
                case 401:
                    return RollbarResponseCode.Unauthorized;
                case 403:
                    return RollbarResponseCode.AccessDenied;
                case 413:
                    return RollbarResponseCode.RequestTooLarge;
                case 422:
                    return RollbarResponseCode.UnprocessablePayload;
                case 429:
                    return RollbarResponseCode.TooManyRequests;
                case 500:
                    return RollbarResponseCode.InternalServerError;
                default:
                    throw new ArgumentException("Invalid Status returned from Rollbar", "status");
            }
        }
    }
    
    public class RollbarResponse {
        public RollbarResponseCode StatusCode { get; set; }
        public string Message { get; set; }
    }

    public enum RollbarResponseCode {
        Success = 200,
        BadRequest = 400,
        Unauthorized = 401,
        AccessDenied = 403,
        RequestTooLarge = 413,
        UnprocessablePayload = 422,
        TooManyRequests = 429,
        InternalServerError = 500,
    }
}