(C#) Outlook Send Email using MIME Format

See more Outlook Examples

This example sends an email using MIME format via the Microsoft Graph Outlook REST API.

For more information, see https://learn.microsoft.com/en-us/graph/api/user-sendmail?view=graph-rest-1.0&tabs=http#example-4-send-a-new-message-using-mime-format

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// 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).

Chilkat.JsonObject jsonToken = new Chilkat.JsonObject();
bool success = jsonToken.LoadFile("qa_data/tokens/microsoftGraph.json");
if (success == false) {
    Debug.WriteLine(jsonToken.LastErrorText);
    return;
}

http.AuthToken = jsonToken.StringOf("access_token");

// To send email, 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.)
// 

// The body of the POST request will contain the MIME source of the email in base64 format.

// Create a new email object
Chilkat.Email email = new Chilkat.Email();
email.Subject = "Test Outlook API to Send HTML Email with Attachments";
email.From = "Mary <mary@somewhere.com>";
email.AddTo("Joe","joe@example.com");

// Add a plain-text alternative body, which will likely never be seen.
// (It is shown if the receiving email client is incapable of displaying HTML email.)
email.AddPlainTextAlternativeBody("This is a plain-text alternative body...");

// Our HTML will include an image, so add the related image here.
string contentIdStarfish = email.AddRelatedFile("qa_data/jpg/starfish.jpg");
if (email.LastMethodSuccess != true) {
    Debug.WriteLine(email.LastErrorText);
    return;
}

// The src attribute for the image tag is set to the contentIdStarfish:
Chilkat.StringBuilder sbHtml = new Chilkat.StringBuilder();
sbHtml.Append("<html><body><p>This is an HTML email with an embedded image.</p>");
sbHtml.Append("<p><img src=\"cid:CONTENT_ID_STARFISH\" /></p></body></html>");
int numReplacements = sbHtml.Replace("CONTENT_ID_STARFISH",contentIdStarfish);

email.AddHtmlAlternativeBody(sbHtml.GetAsString());

// Finally, add some attachments to the email.
// Add a file attachment.
success = email.AddFileAttachment2("qa_data/pdf/fishing.pdf","application/pdf");
if (success != true) {
    Debug.WriteLine(email.LastErrorText);
    return;
}

// Add an attachment where the content is contained in a string.
string content = "This is the content of the 2nd attached file.";
email.AddStringAttachment("someText.txt",content);

// Get the email as multi-line base64..
Chilkat.BinData bdMime = new Chilkat.BinData();
email.GetMimeBd(bdMime);

// Now get it as multi-line base64
Chilkat.StringBuilder sbBase64 = new Chilkat.StringBuilder();
bdMime.GetEncodedSb("base64_mime",sbBase64);

// Send the HTTP POST (i.e. send the email)
Chilkat.HttpResponse resp = http.PTextSb("POST","https://graph.microsoft.com/v1.0/me/sendMail",sbBase64,"utf-8","text/plain",false,false);
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) {
    Chilkat.JsonObject json = new Chilkat.JsonObject();
    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 Mail Sent.");
}