(C#) Outlook Send HTML Email with Embedded Images and Attachments

This example sends an HTML email with both embedded images and attachments. Other examples exist for:

Sending plain-text email.
Sending HTML email.
Sending HTML email with embedded images.
Sending plain-text email with attachments.

Chilkat .NET Downloads

Chilkat .NET Framework

Chilkat for .NET Core

// Important: This example requires Chilkat v9.5.0.68 or greater.

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

Chilkat.Http http = new Chilkat.Http();

// Use your previously obtained access token here:
// See the following examples for getting an access token:
//    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
//    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
//    Refresh Access Token (Azure AD v2.0 Endpoint).
//    Refresh Access Token (Azure AD Endpoint).

http.AuthToken = "MICROSOFT_GRAPH_ACCESS_TOKEN";

// To send mail, we'll POST to the following endpoint:
// 
// POST /users/{id | userPrincipalName}/sendMail
// 
// (The special keyword "me" may be used in place of a principal name.)
// 

// This example will send HTML email containing the following HTML body.
// After the 

// 	<html>
// 	<head>
// 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
// 	<meta content="text/html; charset=utf-8">
// 	</head>
// 	<body bgcolor="#FFFFFF">
// 	<font face="Calibri">This is a test <b>HTML email with embedded images</b>.<br>
// 	<br>
// 	<img alt="" src="cid:starfish"><br>
// 	<img alt="" src="cid:hedgehogs"><br>
// 	</font>
// 	</body>
// 	</html>

// Build the HTML body...
bool bCrlf = true;
Chilkat.StringBuilder sbHtmlBody = new Chilkat.StringBuilder();
sbHtmlBody.AppendLine("<html>",bCrlf);
sbHtmlBody.AppendLine("<head>",bCrlf);
sbHtmlBody.AppendLine("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">",bCrlf);
sbHtmlBody.AppendLine("<meta content=\"text/html; charset=utf-8\">",bCrlf);
sbHtmlBody.AppendLine("</head>",bCrlf);
sbHtmlBody.AppendLine("<body bgcolor=\"#FFFFFF\">",bCrlf);
sbHtmlBody.AppendLine("<font face=\"Calibri\">This is a test <b>HTML email with embedded images</b>.<br>",bCrlf);
sbHtmlBody.AppendLine("<br>",bCrlf);
sbHtmlBody.AppendLine("<img alt=\"\" src=\"cid:starfish\"><br>",bCrlf);
sbHtmlBody.AppendLine("<img alt=\"\" src=\"cid:hedgehogs\"><br>",bCrlf);
sbHtmlBody.AppendLine("</font>",bCrlf);
sbHtmlBody.AppendLine("</body>",bCrlf);
sbHtmlBody.AppendLine("</html>",bCrlf);

// Load the embedded image files.
Chilkat.BinData jpgStarfish = new Chilkat.BinData();
jpgStarfish.LoadFile("qa_data/jpg/starfish.jpg");
Chilkat.BinData jpgHedgeHogs = new Chilkat.BinData();
jpgHedgeHogs.LoadFile("qa_data/jpg/hedgehogs.jpg");

// Load files that are to be attached (not inline images)
Chilkat.BinData attach1 = new Chilkat.BinData();
attach1.LoadFile("qa_data/pdf/fishing.pdf");
Chilkat.BinData attach2 = new Chilkat.BinData();
attach2.LoadFile("qa_data/msword/sample.docx");

// The body of the POST request contains JSON that specifies the email subject, body,
// recipients, etc.  This example will build the following JSON HTML email with
// two embedded images and two attachments.
// 
// The only difference between an embedded inline image and an attachment is that the
// inline image must have a cid that corresponds to the "cid:" found in the "src" attribute
// of an IMG tag within the HTML body of the email.  (The inline image is also marked as "isInline",
// whereas the attachments are not, but I don't know if this actually makes a difference..)
// 

// 	{
// 	  "message": {
// 	    "subject": "Sample HTML Email with Embedded Images and Attachments",
// 	    "body": {
// 	      "contentType": "html",
// 	      "content": "The HTML body goes here..."
// 	    },
// 	    "toRecipients": [
// 	      {
// 	        "emailAddress": {
// 		  "name": "Chilkat Software",
// 	          "address": "admin@chilkat.io"
// 	        }
// 	      },
// 	      {
// 	        "emailAddress": {
// 	          "address": "chilkat.support@gmail.com"
// 	        }
// 	      }
// 	    ],
// 	    "ccRecipients": [
// 	      {
// 	        "emailAddress": {
// 		  "name": "Chilkat Blog",
// 		  "address": "admin@cknotes.com"
// 	        }
// 	      }
// 	    ],
// 	    "attachments": [
// 	       {
// 	         "@odata.type": "#microsoft.graph.fileAttachment",
// 	         "name": "starfish.jpg",
// 	         "contentType": "image/jpeg",
// 	         "size": 6497,
// 	         "isInline": true,
// 	         "contentId": "starfish",
// 	         "contentLocation": null,
// 	         "contentBytes": "base64_data_here"
// 	       },
// 	       {
// 	         "@odata.type": "#microsoft.graph.fileAttachment",
// 	         "name": "hedgehogs.jpg",
// 	         "contentType": "image/jpeg",
// 	         "size": 48845,
// 	         "isInline": true,
// 	         "contentId": "hedgehogs",
// 	         "contentLocation": null,
// 	         "contentBytes": "base64_data_here"
// 	       },
// 	       {
// 	         "@odata.type": "#microsoft.graph.fileAttachment",
// 	         "name": "fishing.pdf",
// 	         "contentType": "application/pdf",
// 	         "size": <theActualSize>,
// 	         "isInline": false,
// 	         "contentBytes": "base64_data_here"
// 	       },
// 	       {
// 	         "@odata.type": "#microsoft.graph.fileAttachment",
// 	         "name": "sample.docx",
// 	         "contentType": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
// 	         "size": <theActualSize>,
// 	         "isInline": false,
// 	         "contentBytes": "base64_data_here"
// 	       }
// 	    ]
// 	  },
// 	  "saveToSentItems": true
// 	}
// 
// Build the above JSON.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("message.subject","Sample HTML Email with Embedded Images and Attachments");
json.UpdateString("message.body.contentType","html");
json.UpdateString("message.body.content",sbHtmlBody.GetAsString());

json.UpdateString("message.toRecipients[0].emailAddress.name","Chilkat Software");
json.UpdateString("message.toRecipients[0].emailAddress.address","admin@chilkat.io");
json.UpdateString("message.toRecipients[1].emailAddress.address","chilkat.support@gmail.com");
json.UpdateString("message.ccRecipients[0].emailAddress.name","Chilkat Blog");
json.UpdateString("message.ccRecipients[0].emailAddress.address","admin@cknotes.com");

json.UpdateString("message.attachments[0].\"@odata.type\"","#microsoft.graph.fileAttachment");
json.UpdateString("message.attachments[0].name","starfish.jpg");
json.UpdateString("message.attachments[0].contentType","image/jpeg");
json.UpdateInt("message.attachments[0].size",jpgStarfish.NumBytes);
json.UpdateBool("message.attachments[0].isInline",true);
// This contentId must match the "cid:" in the HTML
json.UpdateString("message.attachments[0].contentId","starfish");
json.UpdateNull("message.attachments[0].contentLocation");
json.UpdateBd("message.attachments[0].contentBytes","base64",jpgStarfish);

json.UpdateString("message.attachments[1].\"@odata.type\"","#microsoft.graph.fileAttachment");
json.UpdateString("message.attachments[1].name","hedgehogs.jpg");
json.UpdateString("message.attachments[1].contentType","image/jpeg");
json.UpdateInt("message.attachments[1].size",jpgHedgeHogs.NumBytes);
json.UpdateBool("message.attachments[1].isInline",true);
// This contentId must match the "cid:" in the HTML
json.UpdateString("message.attachments[1].contentId","hedgehogs");
json.UpdateNull("message.attachments[1].contentLocation");
json.UpdateBd("message.attachments[1].contentBytes","base64",jpgHedgeHogs);

json.UpdateString("message.attachments[2].\"@odata.type\"","#microsoft.graph.fileAttachment");
json.UpdateString("message.attachments[2].name","fishing.pdf");
json.UpdateString("message.attachments[2].contentType","application/pdf");
json.UpdateInt("message.attachments[2].size",attach1.NumBytes);
json.UpdateBool("message.attachments[2].isInline",false);
json.UpdateBd("message.attachments[2].contentBytes","base64",attach1);

json.UpdateString("message.attachments[3].\"@odata.type\"","#microsoft.graph.fileAttachment");
json.UpdateString("message.attachments[3].name","sample.docx");
json.UpdateString("message.attachments[3].contentType","application/vnd.openxmlformats-officedocument.wordprocessingml.document");
json.UpdateInt("message.attachments[3].size",attach2.NumBytes);
json.UpdateBool("message.attachments[3].isInline",false);
json.UpdateBd("message.attachments[3].contentBytes","base64",attach2);

json.UpdateBool("saveToSentItems",true);

// -------------------------------------------------------------
// Important: This example requires Chilkat v9.5.0.68 or greater.
// -------------------------------------------------------------

// Send the HTTP POST (i.e. send the HTML email)
Chilkat.HttpResponse resp = http.PostJson3("https://graph.microsoft.com/v1.0/me/sendMail","application/json",json);
if (http.LastMethodSuccess != true) {
    Debug.WriteLine(http.LastErrorText);
    return;
}

// The send succeeded if the response status code = 202.
// In the success case, there is no response body.  (We just get the response code to know that it succeeded.)
if (resp.StatusCode != 202) {
    json.Load(resp.BodyStr);
    json.EmitCompact = false;
    Debug.WriteLine(json.Emit());
    Debug.WriteLine("Failed, response status code = " + Convert.ToString(resp.StatusCode));
}
else {
    Debug.WriteLine("Outlook HTML Mail Sent.");
}