Use Outlook 2003 to send meeting request using c#

using System;
using System.Net;
using System.Text;
using System.IO;
using System.Xml;

namespace ExchangeSDK.Snippets.CSharp
{
class SendingAMeetingRequestWebDAV
{
[STAThread]
static void Main(string[] args)
{
// Variables.
string strExchSvrName = "";
string strMailbox = "";
string strCalendarUri = "";
string strMtgItem = "";
string strMtgRequestItem = "";
string strDomain = "";
string strUserName = "";
string strPassword = "";
string strReqAttendees = "";
string strOptAttendees = "";
string strMtgResources = "";
string strMtgRequest = "";
string strMailInfo = "";
string strCalInfo = "";
string strXMLNSInfo = "";
string strHeaderInfo = "";
bool bResult = false;
System.Net.CredentialCache MyCredentialCache = null;
string strUID = "";
string strMapiInfo = "";
string strCCInfo = "";
string strSubmissionUri = "";

try
{
// Exchange server name;
strExchSvrName = "ExchangeServer";

// Mailbox folder of the meeting organizer.
strMailbox = "user1";

// User name and password of the meeting organizer.
strUserName = "user1";
strDomain = "Domain";
strPassword = "!Password";

// Required meeting attendees.
strReqAttendees = "user1@example.com;user2@example.com";

// Optional meeting attendees.
strOptAttendees = "user3@example.com";

// Meeting resources.
strMtgResources = "meetingroom1@example.com";

// Meeting item.
strMtgItem = "testmeeting.eml";

// Meeting request item.
strMtgRequestItem = "testmeetingrequest.eml";

// URI of the user's calendar folder.
strCalendarUri = "http://" + strExchSvrName + "/exchange/"
+ strMailbox + "/Calendar/";

// Create a new CredentialCache object and fill it with the network
// credentials required to access the server.
MyCredentialCache = new System.Net.CredentialCache();
MyCredentialCache.Add( new System.Uri(strCalendarUri),
"NTLM",
new System.Net.NetworkCredential(strUserName, strPassword, strDomain)
);

// XML namespace info for the WebDAV request.
strXMLNSInfo = "xmlns:g=\"DAV:\" "
+ "xmlns:e=\"http://schemas.microsoft.com/exchange/\" "
+ "xmlns:mapi=\"http://schemas.microsoft.com/mapi/\" "
+ "xmlns:mapit=\"http://schemas.microsoft.com/mapi/proptag/\" "
+ "xmlns:x=\"xml:\" xmlns:cal=\"urn:schemas:calendar:\" "
+ "xmlns:dt=\"urn:uuid:c2f41010-65b3-11d1-a29f-00aa00c14882/\" "
+ "xmlns:header=\"urn:schemas:mailheader:\" "
+ "xmlns:mail=\"urn:schemas:httpmail:\"";

// Set the meeting item properties.
strCalInfo = "<cal:location>meetappt Location</cal:location>"
+ "<cal:dtstart dt:dt=\"dateTime.tz\">2004-05-19T23:00:00.000Z</cal:dtstart>"
+ "<cal:dtend dt:dt=\"dateTime.tz\">2004-05-19T23:30:00.000Z</cal:dtend>"
+ "<cal:instancetype dt:dt=\"int\">0</cal:instancetype>"
+ "<cal:busystatus>BUSY</cal:busystatus>"
+ "<cal:meetingstatus>CONFIRMED</cal:meetingstatus>"
+ "<cal:alldayevent dt:dt=\"boolean\">0</cal:alldayevent>"
+ "<cal:responserequested dt:dt=\"boolean\">1</cal:responserequested>";

// Set the required and optional attendees and meeting
// resources of the meeting.
strHeaderInfo = "<header:to>" + strReqAttendees + "</header:to>" +
"<header:cc>" + strOptAttendees + "</header:cc>" +
"<header:bcc>" + strMtgResources + "</header:bcc>";

// Set the subject of the meeting.
strMailInfo = "<mail:subject>Test Meeting Subject</mail:subject>"
+ "<mail:htmldescription>Let's meet here</mail:htmldescription>";

// Build the XML body of the PROPPATCH request.
strMtgRequest = "< xml version=\"1.0\" >"
+ "<g:propertyupdate " + strXMLNSInfo + ">"
+ "<g:set><g:prop>"
+ "<g:contentclass>urn:content-classes:appointment</g:contentclass>"
+ "<e:outlookmessageclass>IPM.Appointment</e:outlookmessageclass>"
+ strMailInfo
+ strCalInfo
+ strHeaderInfo
+ "<mapi:finvited dt:dt=\"boolean\">1</mapi:finvited>"
+ "</g:prop></g:set>"
+ "</g:propertyupdate>";

// Create the meeting item in the organizer's calendar folder.
bResult = CreateMeeting(strCalendarUri + strMtgItem, strMtgRequest, MyCredentialCache);

if(bResult)
{
strUID = FindMeetingUID(strCalendarUri + strMtgItem, MyCredentialCache);

if("" != strUID)
{
// Set the meeting request item contentclass and outlookmessage class properties.
strCCInfo = "<g:contentclass>urn:content-classes:calendarmessage</g:contentclass>" +
"<e:outlookmessageclass>IPM.Schedule.Meeting.Request</e:outlookmessageclass>";

// Set the meeting request item MAPI properties.
strMapiInfo = "<mapi:finvited dt:dt=\"boolean\">1</mapi:finvited>" +
"<mapi:responsestatus dt:dt=\"int\">1</mapi:responsestatus>" +
"<mapi:responsestate dt:dt=\"int\">0</mapi:responsestate>" +
"<mapi:response_requested dt:dt=\"boolean\">1</mapi:response_requested>" +
"<mapi:apptstateflags dt:dt=\"int\">3</mapi:apptstateflags>" +
"<mapi:busystatus dt:dt=\"int\">1</mapi:busystatus>" +
"<mapi:intendedbusystatus dt:dt=\"int\">2</mapi:intendedbusystatus>";

// Build the XML request body of the meeting request item.
strMtgRequest = "< xml version=\"1.0\" >" +
"<g:propertyupdate " + strXMLNSInfo + ">" +
"<g:set><g:prop>" +
strCCInfo +
strMailInfo +
strCalInfo + "<cal:uid>" + strUID + "</cal:uid>" +
strHeaderInfo +
strMapiInfo +
"</g:prop></g:set></g:propertyupdate>";

// Create the meeting request item in the organizer's calendar.
bResult = false;
bResult = CreateMeeting(strCalendarUri + strMtgRequestItem,
strMtgRequest, MyCredentialCache);

if(bResult)
{
// Build the mail submission URI of the meeting organizer.
strSubmissionUri = "http://" + strExchSvrName + "/exchange/" +
strMailbox + "/##DavMailSubmissionURI##/";

// MOVE the meeting request item to mail submission URI (send
// the meeting request).
bResult = false;
bResult = SubmitMeetingRequest(strCalendarUri + strMtgRequestItem,
strSubmissionUri,
MyCredentialCache);
}
}
}
}
catch(Exception ex)
{
// Catch any exceptions.
Console.WriteLine(ex.Message);
}
}

static public bool CreateMeeting(string strMtgUri, string strMtgRequest,
System.Net.CredentialCache MyCredentialCache)
{
// Variables.
System.Net.HttpWebRequest PROPPATCHRequest = null;
System.Net.WebResponse PROPPATCHResponse = null;
byte[] bytes = null;
System.IO.Stream PROPPATCHRequestStream = null;

try
{
// Create the HttpWebRequest object.
PROPPATCHRequest = (System.Net.HttpWebRequest)HttpWebRequest.Create(strMtgUri);

// Add the network credentials to the request.
PROPPATCHRequest.Credentials = MyCredentialCache;

// Specify the PROPPATCH method.
PROPPATCHRequest.Method = "PROPPATCH";

// Set the content type header.
PROPPATCHRequest.ContentType = "text/xml";

// Encode the body using UTF-8.
bytes = Encoding.UTF8.GetBytes((string)strMtgRequest);

// Set the content header length. This must be
// done before writing data to the request stream.
PROPPATCHRequest.ContentLength = bytes.Length;

// Get a reference to the request stream.
PROPPATCHRequestStream = PROPPATCHRequest.GetRequestStream();

// Write the message body to the request stream.
PROPPATCHRequestStream.Write(bytes, 0, bytes.Length);

// Close the Stream object to release the connection
// for further use.
PROPPATCHRequestStream.Close();

// Create the appointment in the Calendar folder of the
// user's mailbox.
PROPPATCHResponse = (System.Net.HttpWebResponse)PROPPATCHRequest.GetResponse();

// Clean up.
PROPPATCHResponse.Close();

Console.WriteLine("Meeting successfully created.");

return true;
}
catch(Exception ex)
{
// Catch any exceptions. Any error codes from the PROPPATCH
// method request on the server will be caught
// here, also.
Console.WriteLine(ex.Message);

return false;
}
}

static public string FindMeetingUID(string strMtgUri,
System.Net.CredentialCache MyCredentialCache)
{
// Variables.
System.Net.HttpWebRequest PROPFINDRequest = null;
System.Net.WebResponse PROPFINDResponse = null;
byte[] bytes = null;
System.IO.Stream PROPFINDRequestStream = null;
string strUIDRequest = "";
System.IO.Stream ResponseStream = null;
XmlDocument ResponseXmlDoc = null;
XmlNodeList UIDNodes = null;
XmlElement elem = null;
XmlAttributeCollection colMultiStatusAtts = null;
string strCalendarPrefix = "";

try
{
// Build the PROPFIND request body.
strUIDRequest = "< xml version='1.0' >" +
"<a:propfind xmlns:a='DAV:'>" +
"<a:prop xmlns:uid='urn:schemas:calendar:'>" +
"<uid:uid/></a:prop>" +
"</a:propfind>";

// Create the HttpWebRequest object.
PROPFINDRequest = (System.Net.HttpWebRequest)HttpWebRequest.Create(strMtgUri);

// Add the network credentials to the request.
PROPFINDRequest.Credentials = MyCredentialCache;

// Specify the PROPPATCH method.
PROPFINDRequest.Method = "PROPFIND";

// Set the content type header.
PROPFINDRequest.ContentType = "text/xml";

// Encode the body using UTF-8.
bytes = Encoding.UTF8.GetBytes((string)strUIDRequest);

// Set the content header length. This must be
// done before writing data to the request stream.
PROPFINDRequest.ContentLength = bytes.Length;

// Get a reference to the request stream.
PROPFINDRequestStream = PROPFINDRequest.GetRequestStream();

// Write the message body to the request stream.
PROPFINDRequestStream.Write(bytes, 0, bytes.Length);

// Close the Stream object to release the connection
// for further use.
PROPFINDRequestStream.Close();

// Create the meeting in the Calendar folder of the
// user's mailbox.
PROPFINDResponse = (System.Net.HttpWebResponse)PROPFINDRequest.GetResponse();

// Get the XML response stream.
ResponseStream = PROPFINDResponse.GetResponseStream();

// Create the XmlDocument object from the XML response stream.
ResponseXmlDoc = new XmlDocument();
ResponseXmlDoc.Load(ResponseStream);

// Get the DAV:multistatus element.
elem = ResponseXmlDoc.DocumentElement;

// Get collection of xmlns attributes.
colMultiStatusAtts = elem.Attributes;

// Get the prefix for the urn:schemas:calendar: namespace.
strCalendarPrefix = "";
foreach (XmlAttribute att in colMultiStatusAtts)
{
// Attribute values are in this format: xmlns:a="DAV:"
if(-1 != att.OuterXml.IndexOf("urn:schemas:calendar:"))
strCalendarPrefix = att.OuterXml.Substring(6,1);
}

// Get the urn:schemas:calendar:uid node (there should only be one).
UIDNodes = ResponseXmlDoc.GetElementsByTagName(strCalendarPrefix + ":uid");

// Clean up.
PROPFINDResponse.Close();
ResponseStream.Close();

if(1 == UIDNodes.Count)
{
Console.WriteLine("Meeting item urn:schemas:calendar:uid found.");
return UIDNodes[0].InnerText;
}
else
{
Console.WriteLine("Meeting item urn:schemas:calendar:uid not found.");
return "";
}
}
catch(Exception ex)
{
// Catch any exceptions. Any error codes from the PROPFIND
// method request on the server will be caught
// here, also.
Console.WriteLine("Meeting item urn:schemas:calendar:uid not found. " + ex.Message);

return "";
}
}

static public bool SubmitMeetingRequest(string strMtgRequestUri, string strSubmissionUri,
System.Net.CredentialCache MyCredentialCache)
{
// Variables.
System.Net.HttpWebRequest MOVERequest = null;
System.Net.WebResponse MOVEResponse = null;

try
{
// Create the HttpWebRequest object.
MOVERequest = (System.Net.HttpWebRequest)HttpWebRequest.Create(strMtgRequestUri);

// Add the network credentials to the request.
MOVERequest.Credentials = MyCredentialCache;

// Specify the MOVE method.
MOVERequest.Method = "MOVE";

// Set the Destination header.
MOVERequest.Headers.Add("Destination", strSubmissionUri);

// Set the content type header.
MOVERequest.ContentType = "message/rfc822";

// Submit the meeting request.
MOVEResponse = (System.Net.HttpWebResponse)MOVERequest.GetResponse();

// Clean up.
MOVEResponse.Close();

Console.WriteLine("Meeting request successfully sent.");

return true;
}
catch(Exception ex)
{
// Catch any exceptions. Any error codes from the MOVE
// method request on the server will be caught
// here, also.
Console.WriteLine("Error sending meeting request: " + ex.Message);

return false;
}
}
}
}