Delphi ActiveX

Get the Content-ID of a Related Item

Demonstrates the Chilkat Email.GetRelatedContentID method, which returns the Content-ID of a related item (typically an image or style sheet embedded within an HTML email). The index is zero-based. This example loads an image from a file into a BinData object, adds it as a related item with AddRelatedBd (capturing the generated Content-ID and referencing it from the HTML), then reads that Content-ID back.

Background: The Content-ID is the anchor that ties an inline resource to the HTML that displays it: the body references cid: plus the ID, and the matching related part carries that same Content-ID. Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd. Reading the Content-ID back lets a program verify or rewrite those links — for example when relocating embedded images or converting a message for display outside a mail client.

Chilkat Delphi ActiveX Downloads

Download Chilkat for Delphi ActiveX

Delphi ActiveX

var
success: Integer;
email: TChilkatEmail;
bdImage: TChilkatBinData;
cid: WideString;
sbHtml: TChilkatStringBuilder;
numReplaced: Integer;
cid0: WideString;

begin
success := 0;

//  Demonstrates the GetRelatedContentID method, which returns the Content-ID of a related
//  item.  Related items are typically images and style sheets embedded within HTML emails.
//  The index is zero-based.

email := TChilkatEmail.Create(Self);
email.Subject := 'GetRelatedContentID example';

//  Load the image data from a file into a BinData object.
bdImage := TChilkatBinData.Create(Self);
success := bdImage.LoadFile('qa_data/images/logo.png');
if (success = 0) then
  begin
    Memo1.Lines.Add(bdImage.LastErrorText);
    Exit;
  end;

//  Add the image as a related item from the BinData; capture its generated Content-ID.
cid := email.AddRelatedBd('logo.png',bdImage.ControlInterface);
if (email.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(email.LastErrorText);
    Exit;
  end;

//  Reference the related item in the HTML body by its Content-ID.
sbHtml := TChilkatStringBuilder.Create(Self);
sbHtml.Append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');
numReplaced := sbHtml.Replace('PLACEHOLDER_CID',cid);
email.SetHtmlBody(sbHtml.GetAsString());

//  Read the Content-ID of the first related item (index 0).
cid0 := email.GetRelatedContentID(0);
Memo1.Lines.Add('Related item 0 Content-ID: ' + cid0);

//  Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
//  relative to the current working directory of the running application.