(VB.NET) Add, Remove, Update MIME Header Fields

Demonstrates how to add, remove, or update the content of MIME header fields.

Chilkat .NET Downloads

Chilkat .NET Framework

Chilkat for .NET Core

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

Dim mime As New Chilkat.Mime

' The contents of this MIME file are shown below, 
' and is also available at https://www.chilkatsoft.com/sampleMime.txt
Dim success As Boolean = mime.LoadMimeFile("qa_data/mime/sampleMime.txt")
If (success <> True) Then
    Debug.WriteLine(mime.LastErrorText)
    Exit Sub
End If


' The MIME used in this example has the following nested structure
' 
' multipart/alternative
'     text/plain
'     multipart/related
'         text/html
'         image/jpeg
' 

' Adding a top-level MIME header is easy.
mime.AddHeaderField("hello-world","Hello World!")
' If a header field of the same name already exists, the AddHeaderField
' method adds a duplicate.
mime.AddHeaderField("Subject","This is the 2nd Subject header.")
Debug.WriteLine(mime.GetEntireHead())
Debug.WriteLine("-")

' The top-level header now looks like this:
' 
' 	Subject: Test email.
' 	Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
' 	MIME-Version: 1.0
' 	hello-world: Hello World!
' 	Subject: This is the 2nd Subject header.
' 

' The RemoveHeaderField method can remove the 1st occurrance, or all occurrences.
Dim bAllOccurrences As Boolean = True
' Remove all occurrences of the Subject header;
mime.RemoveHeaderField("Subject",bAllOccurrences)
Debug.WriteLine(mime.GetEntireHead())
Debug.WriteLine("-")

' After removing all Subject header fields, the top-level header now looks like this:
' 
' Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
' MIME-Version: 1.0
' hello-world: Hello World!
' 

' The content of a header field can be updated by calling SetHeaderField.
' If the header field does not already exist, it is added.  Otherwise it is updated.
' Note: The order of header fields SHOULD never matter.
mime.SetHeaderField("hello-world","Goodbye World.")
Debug.WriteLine(mime.GetEntireHead())
Debug.WriteLine("-")

' Now we have:
' 
' 	Content-Type: multipart/alternative; boundary="------------DB171738719FB06D67DEBAA0"
' 	MIME-Version: 1.0
' 	hello-world: Goodbye World.
' 


' To add/update/delete header fields in sub-parts, navigate to
' the sub-part and do the same..

Dim mpRelated As Chilkat.Mime = mime.GetPart(1)
Dim pJpg As Chilkat.Mime = mpRelated.GetPart(1)

' Add a header to the image/jpeg sub-header.
pJpg.SetHeaderField("CustomHeader","This is the custom header value.")




' View the entire MIME..
Debug.WriteLine(mime.GetMime())



' --------------------------------------------------------------
' --------------------------------------------------------------
' The MIME sample file loaded at the beginning of this example
' contains the following MIME:

' Subject: Test email.
' Content-Type: multipart/alternative;
' 	boundary="------------DB171738719FB06D67DEBAA0"
' MIME-Version: 1.0
' 
' --------------DB171738719FB06D67DEBAA0
' Content-Type: text/plain; charset="utf-8"; format=flowed
' Content-Transfer-Encoding: 7bit
' 
' This is a test.
' 
' --------------DB171738719FB06D67DEBAA0
' Content-Type: multipart/related;
' 	boundary="------------A940F1230E6F0105F03DB2CB"
' 
' --------------A940F1230E6F0105F03DB2CB
' Content-Type: text/html; charset="utf-8"
' Content-Transfer-Encoding: 8bit
' 
' <html><head>
' <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
'   </head>
'   <body bgcolor="#FFFFFF" text="#000000">
'     <p>This is a test.&nbsp; <img src="cid:part1.E16AE3B4.1505C436@chilkatsoft.com" height="20" width="20"></p>
'   </body>
' </html>
' 
' --------------A940F1230E6F0105F03DB2CB
' Content-Type: image/jpeg; name="starfish20.jpg"
' Content-Transfer-Encoding: base64
' Content-ID: <part1.E16AE3B4.1505C436@chilkatsoft.com>
' Content-Disposition: inline; filename="starfish20.jpg"
' 
' /9j/4AAQSkZJRgABAQEASABIAAD//gAmRmlsZSB3cml0dGVuIGJ5IEFkb2JlIFBob3Rvc2hvcD8g
' NC4w/9sAQwAQCwwODAoQDg0OEhEQExgoGhgWFhgxIyUdKDozPTw5Mzg3QEhcTkBEV0U3OFBtUVdf
' YmdoZz5NcXlwZHhcZWdj/9sAQwEREhIYFRgvGhovY0I4QmNjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj
' Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj/8IAEQgAFAAUAwERAAIRAQMRAf/EABcAAAMBAAAA
' AAAAAAAAAAAAAAIDBAX/xAAYAQADAQEAAAAAAAAAAAAAAAABAgMEAP/aAAwDAQACEAMQAAAB2kZY
' NNEijWKddfTmLgALWH//xAAbEAACAgMBAAAAAAAAAAAAAAABAgMRAAQSE//aAAgBAQABBQL0XqN+
' pM2aqJGMiqFFCyg7z//EABwRAAICAgMAAAAAAAAAAAAAAAERAAIQIQMSUf/aAAgBAwEBPwHqU5aq
' Axx+y1tMQl4elj//xAAcEQEAAQUBAQAAAAAAAAAAAAABEQACEBIhA1H/2gAIAQIBAT8B3Bhqy7Zc
' enyiwmGgDhiOzj//xAAdEAABAwUBAAAAAAAAAAAAAAABAAIREBIhIkFR/9oACAEBAAY/ArZyn+Cg
' xtxWuJaoCnqDuin/xAAcEAABBAMBAAAAAAAAAAAAAAABABEhYRAxQVH/2gAIAQEAAT8hkEwPUUR9
' DYfE4nxtRpIkBTsayuALIiuY/9oADAMBAAIAAwAAABDWPTsf/8QAGhEAAwADAQAAAAAAAAAAAAAA
' AAEREDFBIf/aAAgBAwEBPxC0DVPcWm+Ce4OesrkE6bjH/8QAGBEBAQEBAQAAAAAAAAAAAAAAAREA
' QRD/2gAIAQIBAT8QahMiOc8YgSrnTY3ELclHXn//xAAcEAEBAAIDAQEAAAAAAAAAAAABEQAhMUFx
' EFH/2gAIAQEAAT8Qn3igmSZSj+c4N4zapMy9IjFV98wncN2iuLFsCEbDGxQkI6RO/n//2Q==
' 
' --------------A940F1230E6F0105F03DB2CB--
' 
' --------------DB171738719FB06D67DEBAA0--
'