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Posted 11 Mar 2010
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How to Read the Google Calendar in C#

, 24 Mar 2010
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This article will describe how to read the Google calendar using C#


This article describes how to use Google data APIs to read your Google Calendar using C#. It will allow developers to write applications which interact with Google services that will have a number of services such as Calendar, Google Documents, and Contacts, etc.

Synchronization, import, and export of calendars are possible by using APIs. By using Google Calendar service, you can create new events, edit or delete existing events and query for events that match particular criteria.

Note: This article describes only the Google Calendar Service. But in the same manner, you will be able to use other services which Google has provided. Please get the source code for more information.


How to Use Google Data APIs

You have to download the Google data APIs from the below link and install in your machine:

Google data APIs link :

Followings are the references to use Google calendar service:

  1. Google.GData.AccessControl
  2. Google.GData.Client
  3. Google.GData.Extensions

The below three namespaces are required.

  • Google.GData.Calendar namespace has view and update calendar events.
  • Google.GData.Extensions namespace contains common extension elements.
  • Google.GData.Client namespace contains service implementation.
using Google.GData.Calendar;
using Google.GData.Extensions;
using Google.GData.Client;


Since Google Application has become more popular, I decided to write an article about Google application which will be useful for many people.

Sample Application Contains Six Projects


Google Helpers Project

This project has a helper class for Google calendar which has GetService, GetAllEvents and AddEvents methods.

CalendarHelper class has three properties that are used to get service from Google applications. ApplicationName can be anything like "AAA". UserName is your GMail user Id and Password is your GMail password.

public class CalendarHelper
    public string ApplicationName { get; set; }
    public string UserName { get; set; }
    public string Password { get; set; }  
  • GetService method will be accessed by the Google Calendar data API and return the service object:
    public class CalendarHelper
        public static CalendarService GetService(string applicationName, 
    				string userName, string password)
            CalendarService service = new CalendarService(applicationName);
            service.setUserCredentials(userName, password);
            return service;
  • GetAllEvents method reads the calendar data from the Google calendar by using query object. This will require two parameters. CalendarService is the service object that you created in the previous step. startDate is the actual query which you need to query from Google calendar. EventQuery object holds the query.
    public static IEnumerable<EventEntry> GetAllEvents
    		(CalendarService service, DateTime? startData)
          // Create the query object:
          EventQuery query = new EventQuery();
          query.Uri = new Uri("" + 
    			service.Credentials.Username + "/private/full");
          if (startData != null)
              query.StartTime = startData.Value;
          // Tell the service to query:
          EventFeed calFeed = service.Query(query);
          return calFeed.Entries.Cast<EventEntry>();
  • AddEvent method will add new calendar data into Google calendar. Event title, content, location, start time and end time have to be provided.
    • Event title is your new calendar title
    • Content is the description
    • Location is event location
    • Start time is when you plan to start the event
    • End time is when you plan to finish the event
    public static void AddEvent(CalendarService service, string title, 
    	string contents, string location, DateTime startTime, DateTime endTime)
        EventEntry entry = new EventEntry();
        // Set the title and content of the entry.
        entry.Title.Text = title;
        entry.Content.Content = contents;
        // Set a location for the event.
        Where eventLocation = new Where();
        eventLocation.ValueString = location;
        When eventTime = new When(startTime, endTime);
        Uri postUri = new Uri
        // Send the request and receive the response:
        AtomEntry insertedEntry = service.Insert(postUri, entry);
    </li />

Google Adapter Project

This project has GoogleEventsSyncDataSource class which will handle all operations for Helper class which we described above. ISyncDataSource interface is inherited into GoogleEventsSyncDataSource class and these interface signatures such as GetItemHeaders which has type IEnumerable<T> and has one parameter which is lastSyncTime that you need to provide date and time. LoadItemContents has not been used in this sample but you can implement it if you need. WriteItems has IEnumerable<T> type parameter which you need to provide when you write events to Google.


GoogleEventsSyncDataSource contractor will create a service object which you will need later.
Note: You have to change user name and password as required.

namespace GoogleAdapter
    public class GoogleEventsSyncDataSource : ISyncDataSource<GenericEvent>
        CalendarService service;

        public GoogleEventsSyncDataSource()
            service = CalendarHelper.GetService("AAA", "", "mypassword");

        #region ISyncDataSource<GenericEvent> Members

        public string Id
            get { return "Google Calander Sync Data Source"; }

        public IEnumerable<GenericEvent> GetItemHeaders(DateTime? lastSyncTime)
            var googleEvents = CalendarHelper.GetAllEvents(service, lastSyncTime);
            List<GenericEvent> genericEvents = new List<GenericEvent>();
            foreach (var googleEvent in googleEvents)
                GenericEvent genericEvent = new GenericEvent();
                genericEvent.Title = googleEvent.Title.Text;
                genericEvent.Contents = googleEvent.Content.Content;
                genericEvent.Location = googleEvent.Locations.First().ValueString;
                genericEvent.StartTime = googleEvent.Times.First().StartTime;
                genericEvent.EndTime = googleEvent.Times.First().EndTime;
            return genericEvents;

        public void LoadItemContents(IEnumerable<GenericEvent> items)
            //Nothing to load here

        public void WriteItems(IEnumerable<GenericEvent> items)
            foreach (var item in items)
                CalendarHelper.AddEvent(service, item.Title, 
		item.Contents, item.Location, item.StartTime, item.EndTime);


Generic Entities Project

This project has generic event (calendar) which is used to create event collection.


IEquatable interface has been implemented for the comparison of event data if required.

namespace GenericEntities
    public class GenericEvent : IEquatable<GenericEvent>
        public string Title { get; set; }
        public string Contents { get; set; }
        public string Location { get; set; }
        public DateTime StartTime { get; set; }
        public DateTime EndTime { get; set; }

        #region IEquatable<GenericEvent> Members

        public bool Equals(GenericEvent other)
            //Compare all fields to check equality
            if (this.Title == other.Title &&
                this.Contents == other.Contents &&
                this.Location == other.Location &&
                this.StartTime == other.StartTime &&
                this.EndTime == other.EndTime)
                return true;
                return false;


DataSynchronizer Project

SyncManager.cs will return a list of calendars from Google.

namespace DataSynchronizer
    public class SyncManager<T> where T:IEquatable<T>
        public string Name { get; set; }
        public ISyncDataSource<T> Source1 { get; set; }

        public IEnumerable<T> Synchronize(DateTime? lastSyncTime)
                IEnumerable<T> list = Source1.GetItemHeaders(lastSyncTime).ToList();
                return list;
            catch (Exception ex)
                throw ex;

ISyncDataSource.cs interface:

namespace DataSynchronizer
    public interface ISyncDataSource<T> where T : IEquatable<T>
        string Id { get; }
        IEnumerable<T> GetItemHeaders(DateTime? lastSyncTime);
        void LoadItemContents(IEnumerable<T> items);
        void WriteItems(IEnumerable<T> items);

DataSynchronizationService Project

This is a high level service which will be invoked by your application. Here eventManager is generic type of GenericEvent. You will be able to add other Google services by creating helper and generic types.

namespace DataSynchronizer
    public class SyncService
        SyncManager<GenericEvent> eventManager = new SyncManager<GenericEvent>();
        public string LastUpdateDate;
        public SyncService()
            //Initialize Event Manager
            eventManager.Name = "..Event Synchronizer";
            eventManager.Source1 = new GoogleEventsSyncDataSource();

        public IList  SynchronizeEvents()
            IList list = eventManager.Synchronize(DateTime.Now).ToList();
            return list;

How to Test this Application: TestApplication Project

Service instance is a type of SyncService under DataSynchronizationService:

namespace TestApplication
    public partial class Form1 : Form
        SyncService service = new SyncService();
        public Form1()

        private void button1_Click(object sender, EventArgs e)
            IList  list = service.SynchronizeEvents();
            dataGridView1.DataSource = list;


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Pubudu Kasakara
Singapore Singapore
Pubudu Kasakara is working as Solution Architect in Singapore. He has more than 11 years of professional involvement in the IT industry. Worked in successful projects involving mainly the Service Oriented Application by contributing to all requirements gathering, design and implementation phases. He is having experience with SOA applications development, Microsoft .NET, BizTalk, He is member of Charted It professional in UK.

Solution Architect

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Comments and Discussions

QuestionGood post but,Why it is not working? Pin
Nanigarikapati24-Jun-16 8:18
memberNanigarikapati24-Jun-16 8:18 
AnswerRe: Good post but,Why it is not working? Pin
Pubudu Kasakara6-Jul-16 2:25
memberPubudu Kasakara6-Jul-16 2:25 
QuestionCalendar access via Credentials only Pin
vin1497630-Aug-15 21:24
membervin1497630-Aug-15 21:24 
QuestionHow to get Calendar API v3 Pin
JeritFK.22-Apr-15 20:55
memberJeritFK.22-Apr-15 20:55 
QuestionException related Pin
User-1120499510-Feb-15 19:24
memberUser-1120499510-Feb-15 19:24 
AnswerRe: Exception related Pin
Member 1074562919-Feb-15 20:55
memberMember 1074562919-Feb-15 20:55 
QuestionVersion 3 API - possible or not any update than please share your logic please Pin
Nimesh Sapovadiya19-Nov-14 19:49
memberNimesh Sapovadiya19-Nov-14 19:49 
QuestionDoes this still work? Pin
Peter Leijen4-Nov-14 9:21
memberPeter Leijen4-Nov-14 9:21 
AnswerRe: Does this still work? Pin
Gary Medina19-Nov-14 9:27
memberGary Medina19-Nov-14 9:27 
QuestionIs this open source? Pin
i0030-Oct-14 6:32
member i0030-Oct-14 6:32 
QuestionVersion 3 API - possible? Pin
Andrew Truckle26-Jun-14 8:45
professionalAndrew Truckle26-Jun-14 8:45 
AnswerRe: Version 3 API - possible? Pin
Pubudu Kasakara19-Aug-14 23:56
memberPubudu Kasakara19-Aug-14 23:56 
GeneralRe: Version 3 API - possible? Pin
Member 233046418-Nov-14 0:56
memberMember 233046418-Nov-14 0:56 
QuestionEvent color problem Pin
Member 1025784111-Sep-13 2:53
memberMember 1025784111-Sep-13 2:53 
QuestionPassword... Pin
ToddHileHoffer28-May-13 17:42
memberToddHileHoffer28-May-13 17:42 
QuestionHas this API been deprecated? Pin
Member 986221725-Feb-13 1:25
memberMember 986221725-Feb-13 1:25 
QuestionThank you Pin
iosuntrichard11-Jan-13 3:53
memberiosuntrichard11-Jan-13 3:53 
QuestionRead all the calendars Pin
Chindaara19-Dec-12 16:08
memberChindaara19-Dec-12 16:08 
GeneralMy vote of 5 Pin
ravithejag13-Nov-12 20:55
memberravithejag13-Nov-12 20:55 
QuestionCan you use the API to write to the calendar too? Pin
John Pettersson27-Aug-12 4:22
memberJohn Pettersson27-Aug-12 4:22 
QuestionEvent Colors Pin
axsys35620-Mar-12 2:10
memberaxsys35620-Mar-12 2:10 
GeneralMy vote of 5 Pin
ProEnggSoft20-Mar-12 0:37
memberProEnggSoft20-Mar-12 0:37 
GeneralMy vote of 5 Pin
Raymond Verbruggen22-Feb-12 2:33
memberRaymond Verbruggen22-Feb-12 2:33 
GeneralMy vote of 5 Pin
King Coffee6-Feb-12 16:42
memberKing Coffee6-Feb-12 16:42 
GeneralMy vote of 5 Pin
Shahin Khorshidnia1-Feb-12 12:00
professionalShahin Khorshidnia1-Feb-12 12:00 

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