Populating a TreeView with Outlook folders

Wed, 06 Sep 2006 13:25:00 GMT

In this post I will demonstrate how to populate a TreeView with the different Outlook folders. We’ll be using the Outlook Object Model (OOM) to retrieve the folder and some basic information about them. The code itself is well documented, so I’ll not explain it.

private void GetFolders(MAPIFolder currentFolder) { TreeNodeCollection nodes = null ; if (currentFolder == null) // If current folder is null, we’ll be adding the root folders to // the TreeView itself nodes = treeView1.Nodes; else { // otherwise, find th node that represent the MAPIFolder we’re about // to expand TreeNode parentNode = folderToNode[currentFolder] as TreeNode; if (parentNode == null ) throw new ArgumentException("currentFolder"); nodes = parentNode.Nodes; } // If this folder was already expanded, there’s nothing left for us to do if (currentFolder != null && folderExpanded[currentFolder] != null ) return ; else if (currentFolder != null ) { // Otherwise, clear the children nodes of the node we’re about to expand // This is done since we might have placed a Dummy node there - see later if (nodes.Count > 0) nodes.Clear(); // Mark folder as expanded folderExpanded[currentFolder] = true ; } // Retrieve the roo/sub folders Folders folders = (currentFolder == null ? nameSpace.Folders : currentFolder.Folders); foreach (MAPIFolder folder in folders) { // If this folder already has a node, we’re done with it if (folderToNode[folder] != null ) continue ; // Generate a node for the current subfolder TreeNode newNode = GenerateNode(folder); // Add folder to hashes and to it’s parent node nodeToFolder[newNode] = folder; folderToNode[folder] = newNode; nodes.Add(newNode); } }

private TreeNode GenerateNode(MAPIFolder folder) { // Create a new node with the correct name TreeNode newNode = new TreeNode(folder.Name); // Check if and how the number of items should be displayed switch (folder.ShowItemCount) { case OlShowItemCount.olNoItemCount: // Don’t display the number of items break ; case OlShowItemCount.olShowTotalItemCount: // Display the total number of items if (folder.Items.Count > 0) newNode.Text += " (" + folder.Items.Count + ")"; break ; case OlShowItemCount.olShowUnreadItemCount: // Display only the number of unread items if (folder.UnReadItemCount > 0) newNode.Text += " (" + folder.UnReadItemCount + ")"; break ; } // If folder has any subfolders, create a dummy node beneath it. This is // used so that the node will have the nice plus (+) sign next to it // so the user will know there are subfolders. This Dummy node will be // removed once the folder is actually expanded if (folder.Folders.Count > 0) newNode.Nodes.Add(new TreeNode(DummyNode));

return newNode; }

private const string DummyNode = "{1194595F-CAF7-474b-8972-CF143F097243}"; private Hashtable nodeToFolder = new Hashtable(); private Hashtable folderToNode = new Hashtable(); private Hashtable folderExpanded = new Hashtable();

Working with MAPI Items

Wed, 06 Sep 2006 12:08:39 GMT

While the Outlook objects expose most of the properties of the items they represent, sometime they miss the exact field that you need. In this post I'll show you the very basics in retrieving information from the MAPI object that your CDO object represent.

Assuming that you have an Outlook mail item, you need to convert it to a MAPI object. First well need to have a MAPI.Session object:

MAPI.Session session = new MAPI.SessionClass(); session.Logon(null, null, false, false, null, true, Missing.Value);

And now to the actual conversion, which is basically a request for the MAPI object, according to its EntryID:

MAPI.Message message = (MAPI.Message)session.GetMessage(item.EntryID, Missing.Value);

Now that we have our MAPI.Message, well get all its properties (called fields), then well fish out of them the specific required field. After that, you can just get the fields value, and type:

MAPI.Fields fields = message.Fields as MAPI.Fields; MAPI.Field field = fields.get_Item(MAPI.CdoPropTags.CdoPR_SUBJECT, Missing.Value) as MAPI.Field; Console.WriteLine(field.Type.ToString()); Console.WriteLine(field.Value.ToString());

In the above example weve retrieved the items subject. Nothing fancy here, since we could have just as easily get that from the Outlook object. However, if youll have a closer look at the MAPI.CdoPropTags enumeration, youll be able to find many more fields that are not exposed. You can see the values of the enum and the meanings of the different type in a file called MAPITags.h

Itay's space: MAPI/CDO/Outlook

Populating a TreeView with Outlook folders

Working with MAPI Items