So, your trying to get "all properties" using WebDAV.  Well, hate to break it to you, but there is no way unless you know what every property is and specify it.  You will find the same limitation in other messaging APIs - just pick any of them.  Now, you can get many and an even almost every property without having to do too much work.  But be warned, when it comes to messaging APIs having a feature for returning all properties - its really meaning that its going to give you the main ones you would normally care about.  So, if you want "everything" you will need to do a bit of research and coding to get to that point.   For now, lets see how much we can get with WebDAV.

Please note that you really should not try to get every property for your every day applications - thats overkill and a performance killer.   Its best to always select the specific properties you need - its much faster and your appllication has a lesser chance of running into issues (expecially with WebDav and Exoledb which will fail to return properties if there are problems with the Exchange Web Store Schema).

Your basic Allprops:
--------------------
For example, this one will only return 56 properties on a test message in my inbox.  It's the same propfind used by Exchange Explorer for much of its processing:

<?xml version="1.0" ?>
<D:propfind xmlns:D="DAV:">
  <D:allprop/>
</D:propfind>


Large AllProps:
---------------
OK, lets include a bunch of namespaces to try to pull-in more data.  The selection below pulls-in 169 properties.  This is a far cry from the whimpy 56 properties above.  It's quite a bit bigger, but still reasonable.

<?xml version="1.0" ?> <a:propfind 
 xmlns:a='DAV:'
 xmlns:b='urn:schemas:mailheader:'
 xmlns:c='urn:schemas:httpmail:'
 xmlns:d='urn:schemas:contacts:'
 xmlns:e='urn:schemas:calendar:'
 xmlns:f='http://schemas.microsoft.com/exchange/'
 xmlns:g='http://schemas.microsoft.com/mapi/'
 xmlns:h='http://schemas.microsoft.com/mapi/id/'
 xmlns:i='http://schemas.microsoft.com/mapi/proptag/'
 xmlns:j='xml:'
 xmlns:ee='http://schemas.microsoft.com/exchange/events/'
 xmlns:ecga='http://schemas.microsoft.com/mapi/id/{00062008-0000-C0000-000000000046}/'
 xmlns:es='http://schemas.microsoft.com/exchange/security/'
 xmlns:ft='urn:schemas.microsoft.com:fulltextqueryinfo:'
 xmlns:repl='http://schemas.microsoft.com/exchange/events/'
 xmlns:ed='urn:schemas-microsoft-com:exch-data:'
 xmlns:uua='urn:uuid:c2f41010-65b3-11d1-a29f-00aa00c14882/'
 xmlns:of='urn:schemas-microsoft-com:office:forms'
 xmlns:oo='urn:schemas-microsoft-com:office:office'
 xmlns:xd='urn:schemas-microsoft-com:xml-data' >
<a:allprop>
  <a:allprop /><b:allprop /><c:allprop />
  <d:allprop /><e:allprop /><f:allprop />
  <g:allprop /><h:allprop /><i:allprop />
  <j:allprop />
  <ee:allprop /><ecga:allprop /> <es:allprop />
  <ft:allprop /><ed:allprop /><repl:allprop /><of:allprop />
  <oo:allprop /><uua:allprop /><xd:allprop />
</a:allprop>
</a:propfind>


Large Selection
---------------
This one shows 177 properties - thats 8 more.  This one tries to pull a list both dynamicly and using a list of explicit properties. Yes, you do get more - however look at how big this thing is - its a monster.:

<?xml version="1.0" ?> <a:propfind 
 xmlns:a='DAV:'
 xmlns:mh='urn:schemas:mailheader:'
 xmlns:hm='urn:schemas:httpmail:'
 xmlns:sec='http://schemas.microsoft.com/exchange/security/'
 xmlns:cont='urn:schemas:contacts:'
 xmlns:cal='urn:schemas:calendar:'
 xmlns:exch='http://schemas.microsoft.com/exchange/'
 xmlns:g='http://schemas.microsoft.com/mapi/'
 xmlns:h='http://schemas.microsoft.com/mapi/id/'
 xmlns:i='http://schemas.microsoft.com/mapi/proptag/'
 xmlns:j='xml:'
 xmlns:exev='http://schemas.microsoft.com/exchange/events/'
 xmlns:ecga='http://schemas.microsoft.com/mapi/id/{00062008-0000-C0000-000000000046}/'
 xmlns:ft='urn:schemas.microsoft.com:fulltextqueryinfo:'
 xmlns:repl='http://schemas.microsoft.com/exchange/events/'
 xmlns:ed='urn:schemas-microsoft-com:exch-data:'
 xmlns:uua='urn:uuid:c2f41010-65b3-11d1-a29f-00aa00c14882/'
 xmlns:of='urn:schemas-microsoft-com:office:forms'
 xmlns:oo='urn:schemas-microsoft-com:office:office'
 xmlns:xd='urn:schemas-microsoft-com:xml-data' >
<a:allprop>
  <a:allprop /><mh:allprop/><hm:allprop/><sec:allprop/>
  <cont:allprop/><cal:allprop/><exch:allprop/>
  <g:allprop/><h:allprop/><i:allprop/>
  <j:allprop/>
 
  <exev:allprop/><ecga:allprop/>
  <ft:allprop/><ed:allprop /><repl:allprop/><of:allprop/>
  <oo:allprop/><uua:allprop/><xd:allprop/>
</a:allprop>
<a:prop>
  <a:abstract/>
  <a:childcount/>
  <a:comment/>
  <a:contentclass/>
  <a:creationdate/>
  <a:defaultdocument/>
  <a:displayname/>
  <a:getcontentlength/>
  <a:getcontenttype/>
  <a:getetag/>
  <a:getlastmodified/>
  <a:haschildren/>
  <a:hassubs/>
  <a:href/>
  <a:id/>
  <a:iscollection/>
  <a:isfolder/>
  <a:ishidden/>
  <a:isreadonly/>
  <a:isroot/>
  <a:isstructureddocument/>
  <a:lastaccessed/>
  <a:lockdiscovery/>
  <a:nosubs/>
  <a:objectcount/>
  <a:parentname/>
  <a:resourcetype/>
  <a:searchrequest/>
  <a:searchtype/>
  <a:searchrequest/>
  <a:supportedlock/>
  <a:uid/>
  <a:visiblecount/>
  <exch:addressbookdisplayname/>
  <exch:adminfolderdescription/>
  <exch:alias/>
  <exch:altrecipient/>
  <exch:anrcontactsfirst/>
  <exch:archive/>
  <exch:companies/>
  <exch:contentexpiryagelimit/>
  <exch:contentstate/>
  <exch:defaultrevision/>
  <exch:deleteditemflags/>
  <exch:deleteditemsagelimit/>
  <exch:delivcontlength/>
  <exch:deliverandredirect/>
  <exch:deliveryreportrequested/>
  <exch:disableperuserread/>
  <exch:enablereminders/>
  <exch:extensionattribute1/>
  <exch:extensionattribute2/>
  <exch:extensionattribute3/>
  <exch:extensionattribute4/>
  <exch:extensionattribute5/>
  <exch:extensionattribute6/>
  <exch:extensionattribute7/>
  <exch:extensionattribute8/>
  <exch:extensionattribute9/>
  <exch:extensionattribute10/>
  <exch:foldersize/>
  <exch:freebusypublishamount/>
  <exch:hardlinklist/>
  <exch:homemdb/>
  <exch:longdateformat/>
  <exch:mdboverhardquotalimit/>
  <exch:mdboverquotalimit/>
  <exch:mdbstoragequota/>
  <exch:mdbusedefaults/>
  <exch:mid/>
  <exch:mileage/>
  <exch:noaging/>
  <exch:ntsecuritydescriptor/>
  <exch:originaldate/>
  <exch:originaldisplaybcc/>
  <exch:originaldisplaycc/>
  <exch:originaldisplayto/>
  <exch:originalsendername/>
  <exch:originalsubject/>
  <exch:outlookfolderclass/>
  <exch:outlookmessageclass/>
  <exch:patternend/>
  <exch:patternstart/>
  <exch:permanenturl/>
  <exch:publicdelegates/>
  <exch:publicfolderemailaddress/>
  <exch:publishinaddressbook/>
  <exch:receipttime/>
  <exch:recipientlimit/>
  <exch:reminderinterval/>
  <exch:replicationmessagepriority/>
  <exch:replicationschedule/>
  <exch:replicationstyle/>
  <exch:sensitivity/>
  <exch:shortdateformat/>
  <exch:storagequotaissuewarninglimit/>
  <exch:targetaddress/>
  <exch:targetaddress/>
  <exch:textencodedoraddress/>
  <exch:timeformat/>
  <exch:timezone/>
  <exch:weekstartday/>
  <exch:workdayendtime/>
  <exch:workdays/>
  <exch:workdaystarttime/>
  <exch:yomifirstname/>
  <exch:yomilastname/>
  <exch:yomiorganization/>
  <exev:Criteria/>
  <exev:Enabled/>
  <exev:EventMethod/>
  <exev:MatchScope/>
  <exev:Priority/>
  <exev:ScriptUrl/>
  <exev:SinkClass/>
  <exev:TimerExpiryTime/>
  <exev:TimerInterval/>
  <exev:TimerExpiryTime/>
  <exev:TimerStartTime/>
  <sec:admindescriptor/>
  <sec:creator/>
  <sec:descriptor/>
  <sec:lastmodifier/>
  <sec:originalauthor/>
  <sec:originalsender/>
  <sec:originalsentrepresenting/>
  <sec:originator/>
  <sec:readreceiptfrom/>
  <sec:receivedby/>
  <sec:receivedrepresenting/>
  <sec:reportdestination/>
  <sec:reportfrom/>
  <sec:sender/>
  <sec:sentrepresenting/>  <cal:alldayevent/>
  <cal:attendeerole/>
  <cal:attendeestatus/>
  <cal:busystatus/>
  <cal:contacturl/>
  <cal:created/>
  <cal:descriptionurl/>
  <cal:dtend/>
  <cal:dtstart/>
  <cal:exdate/>
  <cal:duration/>
  <cal:exrule/>
  <cal:fburl/>
  <cal:geolatitude/>
  <cal:geolongitude/>
  <cal:instancetype/>
  <cal:isorganizer/>
  <cal:lastmodified/>
  <cal:lastmodifiedtime/>
  <cal:location/>
  <cal:lastmodifiedtime/>
  <cal:locationurl/>
  <cal:meetingstatus/>
  <cal:method/>
  <cal:organizer/>
  <cal:prodid/>
  <cal:rdate/>
  <cal:recurrenceid/>
  <cal:recurrenceidrange/>
  <cal:remindernexttime/>
  <cal:reminderoffset/>
  <cal:replytime/>
  <cal:resources/>
  <cal:responserequested/>
  <cal:rrule/>
  <cal:rsvp/>
  <cal:sequence/>
  <cal:timezone/>
  <cal:timezoneid/>
  <cal:transparent/>
  <cal:uid/>
  <cal:version/>
  <cont:account/>
  <cont:authorig/>
  <cont:bday/>
  <cont:billinginformation/>
  <cont:businesshomepage/>
  <cont:c/>
  <cont:callbackphone/>
  <cont:childrensnames/>
  <cont:cn/>
  <cont:co/>
  <cont:computernetworkname/>
  <cont:customerid/>
  <cont:department/>
  <cont:dn/>
  <cont:email1/>
  <cont:email2/>
  <cont:email3/>
  <cont:employeenumber/>
  <cont:facsimiletelephonenumber/>
  <cont:fileas/>
  <cont:fileasid/>
  <cont:ftpsite/>
  <cont:gender/>
  <cont:givenName/>
  <cont:governmentid/>
  <cont:hobbies/>
  <cont:hobbies/>
  <cont:homeCity/>
  <cont:homeCountry/>
  <cont:homefax/>
  <cont:homelatitude/>
  <cont:homelongitude/>
  <cont:homePhone/>
  <cont:homephone2/>
  <cont:homepostaladdress/>
  <cont:homePostalCode/>
  <cont:homepostofficebox/>
  <cont:homeState/>
  <cont:homeStreet/>
  <cont:hometimezone/>
  <cont:initials/>
  <cont:internationalisdnnumber/>
  <cont:l/>
  <cont:language/>
  <cont:location/>
  <cont:mailingaddressid/>
  <cont:mailingcity/>
  <cont:mailingcountry/>
  <cont:mailingpostaladdress/>
  <cont:mailingpostalcode/>
  <cont:mailingpostofficebox/>
  <cont:mailingstate/>
  <cont:mailingstreet/>
  <cont:manager/>
  <cont:mapurl/>
  <cont:members/>
  <cont:middlename/>
  <cont:mobile/>
  <cont:namesuffix/>
  <cont:nickname/>
  <cont:o/>
  <cont:office2telephonenumber/>
  <cont:officetelephonenumber/>
  <cont:organizationmainphone/>
  <cont:othercity/>
  <cont:othercountry/>
  <cont:othercountrycode/>
  <cont:otherfax/>
  <cont:othermobile/>
  <cont:otherpager/>
  <cont:otherpostaladdress/>
  <cont:otherpostalcode/>
  <cont:otherpostofficebox/>
  <cont:otherstate/>
  <cont:otherstreet/>
  <cont:otherTelephone/>
  <cont:othertimezone/>
  <cont:pager/>
  <cont:personalHomePage/>
  <cont:personaltitle/>
  <cont:postalcode/>
  <cont:postofficebox/>
  <cont:profession/>
  <cont:proxyaddresses/>
  <cont:referredby/>
  <cont:roomnumber/>
  <cont:secretary/>
  <cont:secretarycn/>
  <cont:secretaryphone/>
  <cont:secretaryurl/>
  <cont:sn/>
  <cont:sourceurl/>
  <cont:spousecn/>
  <cont:st/>
  <cont:street/>
  <cont:submissioncontlength/>
  <cont:telephoneNumber/>
  <cont:telephoneNumber2/>
  <cont:telexnumber/>
  <cont:title/>
  <cont:ttytddphone/>
  <cont:unauthorig/>
  <cont:usercertificate/>
  <cont:weddinganniversary/>
  <cont:workaddress/>  <hm:bcc/>
  <hm:attachmentfilename/>
  <hm:calendar/>
  <hm:cc/>
  <hm:content-disposition-type/>
  <hm:content-media-type/>
  <hm:date/>
  <hm:datereceived/>
  <hm:from/>
  <hm:hasattachment/>
  <hm:htmldescription/>
  <hm:importance/>
  <hm:normalizedsubject/>
  <hm:priority/>
  <hm:reply-to/>
  <hm:sender/>
  <hm:subject/>
  <hm:textdescription/>
  <hm:thread-topic/>
  <hm:deleteditems/>
  <hm:displaybcc/>
  <hm:displaycc/>
  <hm:displayto/>
  <hm:drafts/>
  <hm:expiry-date/>
  <hm:flagcompleted/>
  <hm:fromemail/>
  <hm:fromname/>
  <hm:inbox/>
  <hm:journal/>
  <hm:messageflag/>
  <hm:msgfolderroot/>
  <hm:notes/>
  <hm:outbox/>
  <hm:read/>
  <hm:reply-by/>
  <hm:savedestination/>
  <hm:saveinsent/>
  <hm:senderemail/>
  <hm:sendername/>
  <hm:sendmsg/>
  <hm:sentitems/>
  <hm:submitted/>
  <hm:tasks/>
  <hm:unreadcount/>
  <hm:to/>
  <mh:approved/>
  <mh:bcc/>
  <mh:cc/>
  <mh:comment/>
  <mh:content-base/>
  <mh:content-description/>
  <mh:content-disposition/>
  <mh:content-id/>
  <mh:content-language/>
  <mh:content-location/>
  <mh:content-transfer-encoding/>
  <mh:content-type/>
  <mh:control/>
  <mh:date/>
  <mh:disposition/>
  <mh:disposition-notification-to/>
  <mh:distribution/>
  <mh:expires/>
  <mh:expiry-date />
  <mh:followup-to/>
  <mh:from/>
  <mh:importance/>
  <mh:in-reply-to/>
  <mh:keywords/>
  <mh:lines/>
  <mh:message-id/>
  <mh:mime-version/>
  <mh:newsgroups/>
  <mh:organization/>
  <mh:original-recipient/>
  <mh:path/>
  <mh:posting-version/>
  <mh:priority/>
  <mh:received/>
  <mh:reply-by/>
  <mh:reply-to/>
  <mh:references/>
  <mh:relay-version/>
  <mh:return-path/>
  <mh:return-receipt-to/>
  <mh:sender/>
  <mh:sensitivity/>
  <mh:subject/>
  <mh:summary/>
  <mh:thread-index/>
  <mh:thread-topic/>
  <mh:to/>
  <mh:x-mailer/>
  <mh:x-message-completed/>
  <mh:x-message-flag/>
  <mh:xref/>
  <mh:x-unsent/>
  <ed:baseschema/>
  <ed:closedexpectedcontentclasses/>
  <ed:codebase/>
  <ed:comclassid/>
  <ed:comprogid/>
  <ed:default/>
  <ed:dictionary/>
  <ed:expected-content-class/>
  <ed:iscontentindexed/>
  <ed:isindexed/>
  <ed:ismultivalued/>
  <ed:ismultivalued/>
  <ed:isrequired/>
  <ed:isvisible/>
  <ed:propertydef/>
  <ed:schema-collection-ref/>
  <ed:synchronize/>
  <ed:version/>  <repl:changetype/>
  <repl:collblob/>
  <repl:contenttag/>
  <repl:repl/>
  <repl:repl-uid/>
  <repl:resourcetag/>
  <repl:resourcetaglist/></a:prop>
</a:propfind>