Develop Reference

C# Outlook Add-in: How can I delete a User-defined property programmatically?

I have tried finding an answer to this question practically everywhere I could imagine, including here on StackOverflow. Unfortunately to no avail. So here it is.
I'm working on an Outlook Add-in (with Outlook 2021), and have developed some code that creates some ItemProperties specifically for use with that add-in. Now, when those properties are created, I can see them when I go to View->Settings->Advanced View Settings->Columns, as illustrated in the screenshot.
Screenshot of User-defined fields in Outlook
In some cases, though, I want to completely delete the properties. And as I know how to do that manually, as pointed out in the figure, I can't find out how to do that programmatically via C#. I have gone that far as to remove the properties from each mail containing that kind of property, like this:
IEnumerable<MailItem> listOfAssignedEmails = itemsToProcess.Where(
t => t.ItemProperties[MailExpiration.ExpirationDatePropertyName] != null);
foreach (MailItem email in listOfAssignedEmails)
{
// Note: The Delete() operation is deprecated. A more up-to-date method must be found.
email.ItemProperties[MailExpiration.ExpirationDatePropertyName].Delete();
email.Save();
}
... and yes, I know that the Delete() operation is deprecated; however, I couldn't find another method for removing the ItemProperty from the email (any suggestions are welcome).
Basically, the deletion of this Property is only going to be done very rarely (t. ex. if the user chooses to uninstall the Add-in. However, if there's any way to remove that property automatically, I would be happy to know.
Any suggestions will be greatly appreciated.

It is really a bad idea to remove a custom property from all emails that already have it: there is really no point since the user will never see them, but you will have to retouch (and thus change the last modified date) of a large number of emails.
Also note that named properties in MAPI are a finite resource - you can have at most 64k of them in a mailbox. Once a particular property mapping is used, you can never unmap it, even if there are no items that use that property.
Thirdly, doing anything Outlook related from an installer (rather than a VSTO addin) is a really bad idea - Windows installer runs in a service.
If you want to make sure the user no longer sees your custom fields as available properties in a view, you need to deal with the folder fields - they ar stored in a blob in a hidden (associated) message in that folder. OOM does not expose folder fields at all (if you don't count the AddToFolderFields parameter when calling UserProperties.Add). If using Redemption is an option (I am its author), it exposed RDOFolderFields object (accessible from RDOFolder2.FolderFields property) that allows to add or delete folder fields.

The list of properties shown on the screenshot belongs to the Folder.UserDefinedProperties property which returns a UserDefinedProperties object that represents the user-defined custom properties for the Folder object.
Use the ItemProperties.Remove method removes an object from the collection (from an item).
Use the ItemProperties property to return the ItemProperties collection. Use ItemProperties.Item(index), where index is the name of the object or the numeric position of the item within the collection, to return a single ItemProperty object.

Sitecore Custom Rules

I have a custom rule in Sitecore:
where person's status is [condition,Tree,root=/sitecore/content/Home/PersonStates, specified state]
I want to replace the hard coded path with one that points to any folder that has it's template id matching the one I specified. This is because the author will create these values (of a specific template in the root folder).
I have tried this and it does not work:
where person's status is [condition,Tree,root=query:/sitecore/content/Common/Categories/*[##templateid='{3B0461BF-9ABC-4AF1-B937-C8D225FC2313}'], specified state]
Furthermore, I need to restrict some of these values based on properties that these items would have.
Eg: The author adds 5 states. I need only those states which have the active flag set to true.
How would I do this?

Out of the box the Tree Macro does not support this, the solution is to create a custom Macro that allows a query to be executed. In order to do this you will have to implement IRuleMacro and implement your logic. Make sure to URL encode your query. Also note that the macro does not have any context when called, so you will have to implement this yourself. An example of this can be found here

How to write a Wix Custom Action to Read XML data and set Properties

I have been working on this for days and I just don't get the concept of how Custom Actions work with Wix. Or at least I don't see how to do what I want.
I have several XML files that I want to read a value from and populate a property that gets displayed in a UI Dialog. Then when the install begins update that value in another XML file.
I need to be able to pass the filename including path of the local XML file and the node to search for and the key value pair to extract. I also need to pass what property needs to be updated.
I understand the CustomAction DLL concept. And that the session.CustomActionData["parametername"] syntax for passing in parameters. And the session["property"] = to set a property.
But I can't figure out the syntax of the wsx code to make it all happen. I read different examples doing it different ways?
I searched all the Google links out there an nothing seems to fit what I want to do?

You want this to be an immediate custom action not a deferred custom action so CustomActionData has no relevance to you.
What I would do is write a custom table like such:
Id [PK]
File (Formatted)
XPATH
Property
Here's an example:
mySearch
[SOMEPROPERTY]
/test[#'test'] (something like that, I hate xpath)
MYPROPERTY
You can use things like Property/FileSearch to have MSI's AppSearch resolve the location of a file and assign it to [SOMEPROPERTY]. Then you write a custom action scheduled after AppSearch to fetch this table's data, iterate it and fetch the attribute value (or element innertext) of each row and assign it to MYPROPERTY.
InstallShield gave this to me for free. I don't think WiX has a built in extension to do this. Maybe there is a community extension out there. It would probably take me an hour to write a prototype of this in C#/DTF.

Modify FieldDefinitions programmatically

There is currently a need within our shop to be able to add/modify/delete the FieldDefinitions on a WorkItemStore programmatically, without/before messing with the WorkItemType definitions. Is this possible? I know that i can GET all the fields on a project and see them, but what about adding new ones, or modifying existing ones ? (delete not as important).
i've been searching google for the past 2 days and couldn't find what i'm looking for...
Right now, this is how i am reading all the fields from the server.
List<FieldDefinition> all_defs = new List<FieldDefinition>();
FieldDefinitionCollection defs = wis.FieldDefinitions;
foreach(FieldDefinition def in defs)
all_defs.Add(def);

I was able to do a workaround. Basically, in code, I was able to get all of the fields on the server, create all of the fields that I needed to add or modify and then export one WIT as XML into a separate string.
From there, I extracted the new fields that I needed by comparison, modified the fields that I needed to modify (in Xml), changed the name of the WIT (in Xml) into a temporary one (e.g.: Missing_fields), then modified the WIT Xml to include both the new fields and the modified ones inside the Fields tag...
Then I used the Import WIT method on the temporary WIT I just created...
Then I refreshed the connection cache for the API... (this ensures the API has access to the new WIT so we can delete it)
Then I used the DestroyWIT action package to destroy the temporary WIT from the server, which essentially destroys the WIT itself, but not the fields as those are a separate entity on the server, and voilà! You've got yourself a FieldDefinition import and modify tool.
I still can't delete but that's not too bad...

Winforms - Dynamic Load / Save Settings

I have a "settings file" in my Winforms application called Settings.settings with a partial class for custom methods, etc. Is there a way to load / save dynamic settings based on arbitrary keys?
For example, I have some ListViews in my application in which I want to save / load the column widths; Instead of creating a width setting for each column for each list view I would like a simple method to load / save the widths automatically.
Below is an example of the save method I have tried:
internal sealed partial class Settings
{
public void SetListViewColumnWidths(ListView listView)
{
String baseKey = listView.Name;
foreach (ColumnHeader h in listView.Columns)
{
String key = String.Format("{0}-{1}", baseKey, h.Index);
this[key] = h.Width;
}
}
}
When running that code I get the error "The settings property 'TestsListView-0' was not found." Is there something I am missing?

Store your column width settings in an Xml Serializable object. Ie, something that implements IXmlSerializable then create a single setting entry of that type in Settings.settings.
A good option would probably be an Xml Serializable Dictionary. A quick google search found quite a few different blog posts that describe how to implement that.
As mentioned in other answers you'll need to ensure that this object is a User setting. You may also need to initialize the setting instance. Ie, create a XmlSerializableDictionary() instance and assign it to the setting if the setting is null. The settings subsystem doesn't create default instances of complex setting objects.
Also, if you want these settings to persist between assembly versions (ie, be upgradable) you will need to upgrade the settings on application startup. This is described in detail on Miha Markič's blog and Raghavendra Prabhu's blog.

I think the error
The settings property
'key' was not found.
occurs because the 'key' value does not exist in your settings file (fairly self-explanatory).
As far as I am aware, you can't add settings values programmatically, you might need to investigate adding all of the settings you need to the file after all, although once they are there, I think you'll be able to use the sort of code you've given to save changes.
To Save changes, you'll need to make sure they are 'User' settings, not 'Application'.
The Settings file is quite simple XML, so you might be able to attack the problem by writing the XML directly to the file, but I've never done it, so can't be sure it would work, or necessarily recommend that approach.
http://msdn.microsoft.com/en-us/library/cftf714c.aspx is the MSDN link to start with.

You can do Settings.Save() or similar on user settings, but note that such settings would NOT get persisted to the xxx.exe.config file in your app directory as you'd expect. They actually go somewhere deep inside the user folder (search your drive for xxx.exe.config to find it). Next time that you manually change xxx.exe.config in your app directory, the change will mysteriously not apply (the system is still using the saved one from the user directory).