Sample code for 30+ languages & platforms
C#

Create Email Folder (sub-Mailbox)

How to create a new email folder (sub-mailbox). (In GMail, folders are called "labels". This example would create a new "label" in GMail.)

Chilkat C# Downloads

C#
bool success = false;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Imap imap = new Chilkat.Imap();

imap.Ssl = true;
imap.Port = 993;

// Connect to an IMAP server.
success = imap.Connect("imap.gmail.com");
if (success != true) {
    Debug.WriteLine(imap.LastErrorText);
    return;
}

// Login
success = imap.Login("myLogin","myPassword");
if (success != true) {
    Debug.WriteLine(imap.LastErrorText);
    return;
}

// Create the new email folder (sub-mailbox) on the IMAP server.
// If no folder path is provided, the new folder is a sub-mailbox of Inbox.
success = imap.CreateMailbox("newFolder");
if (success != true) {
    Debug.WriteLine(imap.LastErrorText);
    return;
}

// (In GMail, folders are called "labels".  
// This example would create a new "label" in GMail.)

// Now create a sub-folder under "newFolder".
// Make sure to use the proper separator char for your IMAP server.
// The separator char used here is "/".   It is typically "/" or ".".
// The SeparatorChar property contains the separator char
// that should be used for the current IMAP session.
success = imap.CreateMailbox("newFolder/subFolder_A");
if (success != true) {
    Debug.WriteLine(imap.LastErrorText);
    return;
}

Debug.WriteLine("Success.");