Why is the EntryID Changing in VSTO? The MailItem is not moving folders

Question

I'm writing some code in C# that matches a pattern from the subject and then ingests the email. To initialize my datastore, I go through the current Microsoft.Office.Interop.Outlook.Table.

while (!table.EndOfTable)
{
    Row row = table.GetNextRow();

    string entryId = row["EntryID"].ToString();
    this.SaveInXML(entryId, row);
}

It seems pretty simple. Well, I also have an event (Application.ItemLoad) that I'm watching, too. I notice that in the event the MailItem's EntryID is completely different than the Table's EntryID. In fact, the string lengths are not even the same (See example below). Why is this? Shouldn't they be the same? The item has not moved folders, so I'd assume it's the same. Thank you, all.

Example code:

NameSpace ns = this.Folder.Application.GetNamespace("MAPI");
var mi = ns.GetItemFromID("EF0000003E65593F1D361C44AFBFA24E6F365D6E04782F00") as MailItem;
string entryId = mi.EntryID;

System.Diagnostics.Debug.WriteLine("EF0000003E65593F1D361C44AFBFA24E6F365D6E04782F00");
System.Diagnostics.Debug.WriteLine(entryId);

// Output Produced:
// EF0000003E65593F1D361C44AFBFA24E6F365D6E04782F00
// 000000003E65593F1D361C44AFBFA24E6F365D6E0700CC348F1AD97A224B9898503750437E4700000000010C0000CC348F1AD97A224B9898503750437E470000F59160590000
//
// Notice that the second WriteLine isn't even remotely close to the EntryID that I requested.

Answer 1

Entry identifiers come in two types: short-term and long-term.

Short-term entry identifiers are faster to construct, but their uniqueness is guaranteed only over the life of the current session on the current workstation.

Long-term entry identifiers have a more prolonged lifespan. Short-term entry identifiers are used primarily for rows in tables and entries in dialog boxes, whereas long-term entry identifiers are used for many objects such as messages, folders, and distribution lists.

Use the MailItem.EntryID property if you need to get a long-term entry identifiers.

Entry identifiers cannot be compared directly because one object can be represented by two different binary values. Use the NameSpace.CompareEntryIDs method to determine whether two entry identifiers represent the same object.