Author: Nishant Rana

We can make use of below sample code to set the Time Off for the user programmatically. In the below code we are setting time off of duration 8 hours on 7^th May 2013.

IServiceManagement<IOrganizationService> orgServiceManagement =
 ServiceConfigurationFactory.CreateManagement<IOrganizationService>(new Uri("https://orgname.crm5.dynamics.com/XRMServices/2011/Organization.svc"));

AuthenticationCredentials authCredentials = new AuthenticationCredentials();
 authCredentials.ClientCredentials.UserName.UserName = "user@domain.onmicrosoft.com";
 authCredentials.ClientCredentials.UserName.Password = "password";
 AuthenticationCredentials tokenCredentials = orgServiceManagement.Authenticate(authCredentials);

OrganizationServiceProxy organizationProxy = new OrganizationServiceProxy(orgServiceManagement, tokenCredentials.SecurityTokenResponse);

 // Get the user id
 Guid userid = ((WhoAmIResponse)organizationProxy.Execute(new WhoAmIRequest())).UserId;

// Get the calendar id of the user
 Entity systemUserEntity = organizationProxy.Retrieve("systemuser", userid, new ColumnSet(new String[] { "calendarid"}));

// Retrieve the calendar of the user
 Entity userCalendarEntity = organizationProxy.Retrieve("calendar", ((Microsoft.Xrm.Sdk.EntityReference)(systemUserEntity.Attributes["calendarid"])).Id, new ColumnSet(true));

// Retrieve the calendar rules defined in the calendar
 EntityCollection calendarRules = (EntityCollection)userCalendarEntity.Attributes["calendarrules"];

// Create a new inner calendar
 Entity newInnerCalendar = new Entity("calendar");
 newInnerCalendar.Attributes["businessunitid"] = new EntityReference("businessunit", ((Microsoft.Xrm.Sdk.EntityReference)(userCalendarEntity["businessunitid"])).Id);
 Guid innerCalendarId = organizationProxy.Create(newInnerCalendar);

// Create a new calendar rule and assign the inner calendar id to it
 Entity calendarRule = new Entity("calendarrule");
 calendarRule.Attributes["description"] = "Time Off Rule";
 calendarRule.Attributes["duration"] = 480;
 calendarRule.Attributes["extentcode"] = 2;
 calendarRule.Attributes["pattern"] = "FREQ=DAILY;INTERVAL=1;COUNT=1";
 calendarRule.Attributes["rank"] = 0;
 calendarRule.Attributes["timezonecode"] = 190;
 calendarRule.Attributes["innercalendarid"] = new EntityReference("calendar", innerCalendarId);

// starting at 12:00 on 7 May
 calendarRule.Attributes["starttime"] = new DateTime(2013, 5, 7,0,0,0,DateTimeKind.Utc);
 calendarRules.Entities.Add(calendarRule);

// assign all the calendar rule back to the user calendar
 userCalendarEntity.Attributes["calendarrules"] = calendarRules;
 // update the user calendar entity that has the new rule
 organizationProxy.Update(userCalendarEntity);

Entity calendarRule1 = new Entity("calendarrule");

// duration of 8 hours
 calendarRule1.Attributes["duration"] = 480;
 calendarRule1.Attributes["effort"] = 2.0;
 calendarRule1.Attributes["issimple"] = true;


 calendarRule1.Attributes["offset"] = 0;
 calendarRule1.Attributes["rank"] = 0;
 // subcode 6= vacation
 calendarRule1.Attributes["subcode"] = 6;
 // time code 2 = unavailable
 calendarRule1.Attributes["timecode"] = 2;
 calendarRule1.Attributes["timezonecode"] = -1;
 calendarRule1.Attributes["calendarid"] = new EntityReference("calendar", innerCalendarId);

EntityCollection innerCalendarRules = new EntityCollection();
 innerCalendarRules.EntityName = "calendarrule";
 innerCalendarRules.Entities.Add(calendarRule1);

newInnerCalendar.Attributes["calendarrules"] = innerCalendarRules;
 newInnerCalendar.Attributes["calendarid"] = innerCalendarId;
 organizationProxy.Update(newInnerCalendar);

Hope it helps