// For a given project's application form, upload a PDF file as a utility bill attachment.
// Returns true if the upload completed successfully, false otherwise.

public bool UploadUtilityBill(string programId, string projectId, string formId, string utilityBillAttachmentId, string filePath, string username, string password, string apiKey)
{
    // Retrieve the file and prepare it for uploading
    byte[] fileContents = File.ReadAllBytes(filePath);
    StreamContent payload = new StreamContent(new MemoryStream(fileContents));

	// Create the url for the upload
    string url = "/Programs/" + programId + "/Projects/" + projectId + "/Forms/" + formId +
"/Attachments/" + utilityBillAttachmentId + "/Upload";

    // Make POST request to upload the attachment
    XDocument xmlResponse = null;
    using (HttpClient webClient = new HttpClient())
    {
        string authHeader = EncodeAuthorizationHeader(username, password);
        string fileName = Path.GetFileName(filePath);

		payload.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
        {
            Name = "\"file\"",
            FileName = "\"" + fileName + "\""
        };
        string contentType = "application/pdf"; // pdf
        payload.Headers.ContentType = MediaTypeHeaderValue.Parse(contentType);

		webClient.DefaultRequestHeaders.Clear();
        webClient.DefaultRequestHeaders.Add("Authorization", authHeader);
        webClient.DefaultRequestHeaders.Add("X-ApiKey", apiKey);
        using (HttpResponseMessage response = webClient.PostAsync(BaseUrl + url, payload).Result)
        {
            xmlResponse = XDocument.Parse(response.Content.ReadAsStringAsync().Result);
        }
    }
    // If the response has exactly one Attachment element, the upload has completed successfully
    XNamespace ns = "http://service.powerclerk.com/api/v1/";
    List<XElement> attachmentElements = xmlResponse.Descendants(ns + "Attachment").ToList();
    if (attachmentElements.Count != 1)
    {
        return false;
    }
    return true;
}