I doubt that will help, not least if you are using Exchange: on the low
level, user proeprties are stored as named MAPI properties. To get a
property tag, Outlook calls IMessage::GetIDsFromNames passing the GUID
(PS_PUBLIC_STRING for the user properties) and id (the property name in
your case, can also be an integer).
Once a particular combination of GUID/id is mapped to a tag (4 bytes
int), it will always be used for that store (mailbox). The very first
time that tag is used when setting a property, the store will remember
the property type (PT_BOOLEAN, PT_SYSTIME, etc).
You cannot make the store forget about a particular property, once it is
used, the type cannot be changed.
--
Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool
-
My senior programmer whose work I am trying to debug decided that
whenever he wanted to add user property to a mail item, he would
include the third
parameter as True. That is, adding the user-defined field to the folder
as well.
Using the Outlook GUI just now I have seen a few user fields that have
Yes/No type in the "User-Defined Fields in Inbox" but for the
particular item, the field type is Date/Time. So there is inconsistency
there.
I'm am guessing to remedy the whole thing I'll go through and delete
all user defined fields in all folders -- Inbox, Sent Items etc.
Then I am thinking to amend his code below labeled "//Create user
property if does not exist", making the third parameter False instead
of True.
Is there any downside to not having the user-defined fields mirrored in
the Folders?
Our code in other places does things like Advanced Search based on
user-defined field values.
I'd be interested to know best practice here -- it's for an Outlook
2007 VSTO C# Add-in for various different external clients.
It ios not just on a particular message - themapping is on thestore
level,
plus you added the user property to teh folder props (thrird parameter
=
true).
--
Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool
-
The thing is I always get the error message:
'mail.UserProperties[propertyName]' is null
if I try to set its value though. Here's some immediate window
results:
?mail.UserProperties[propertyName] == null
true
mail.UserProperties.Add(propertyName, propType, true, Type.Missing)
'mail.UserProperties.Add(propertyName, propType, true, Type.Missing)'
threw an exception of type
'System.Runtime.InteropServices.COMException'
base {System.Runtime.InteropServices.ExternalException}: {"A
custom
field with this name but a different data type already exists. Enter
a
different name."}
mail.UserProperties[propertyName].Value = value;
'mail.UserProperties[propertyName]' is null
?mail.UserProperties[propertyName].GetType()
'((object)(mail.UserProperties[propertyName]))' is null
?mail.UserProperties[propertyName].IsUserProperty
'mail.UserProperties[propertyName]' is null
mail.UserProperties[propertyName].Value = 0;
'mail.UserProperties[propertyName]' is null
I think this is as self-explanatory as it gets: you already have a
property with the same name but a different property type.
Once you used a particular type for any given name, you are stuck
with
that type.
--
Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool
-
VSTO C# Outlook 2007.
Does anyone know why I am getting the following exception from the
code
below and what the solution is?
"Exception while setting up user property:
A custom field with this name but a different data type already
exists.
Enter a different name.
Prop name = x-MYAPP-MyDate1
Value=21/11/2009 3:01:30 a.m.
Type = olDateTime"
private void SetProperty(string propertyName, object value,
Outlook.OlUserPropertyType propType)
{
try
{
//Create user property if does not exist
if (mail.UserProperties[propertyName] == null)
{
mail.UserProperties.Add(propertyName, propType,
true, Type.Missing);
}
//Set property value
if (value != null)
{
mail.UserProperties[propertyName].Value = value;
}
//Delete the property if value was null
else
{
mail.UserProperties[propertyName].Delete();
}
}
catch (Exception e)
{
string msg = "Exception while setting up user
property:\n" + e.Message + "\n"
+ "Prop name = " + propertyName + "\nValue=" +
value.ToString() + "\nType = " + propType;
MYAPP.LogMessage(msg);
}
}
