Send Messages with Files

This guide explains how to send file attachments securely.

Two Methods for Attaching Files

  1. By file path (FilesPath) - Files on disk
  2. By binary content (FileArgs) - Files in memory

Method 1: Files by Path

Quick Example

var args = new MutliRecipientArgs(
    endpoint, serial, apiUser, apiPassword,
    recipients, message, subject,
    null, null, SendMethodEnum.onlyEmail,
    false, true, true, "en-CA", 5, 1440
);

// Add files by their path
args.FilesPath = new List<string>
{
    @"C:\Documents\report.pdf",
    @"C:\Documents\invoice.xlsx"
};

var response = MessageHelper.MultiRecipientMessage(args);

Complete Example: Sending Contract Documents

using System;
using System.Collections.Generic;
using System.IO;
using SecureExchangesSDK.Helpers;
using SecureExchangesSDK.Models.Args;
using SecureExchangesSDK.Models.Entity;
using SecureExchangesSDK.SecureExchanges;

public class ContractDeliveryService
{
    private readonly Guid _serial;
    private readonly Guid _apiUser;
    private readonly Guid _apiPassword;

    public ContractDeliveryService(Guid serial, Guid apiUser, Guid apiPassword)
    {
        _serial = serial;
        _apiUser = apiUser;
        _apiPassword = apiPassword;
    }

    /// <summary>
    /// Sends a contract with its annexes
    /// </summary>
    public SendResult SendContract(
        string recipientEmail,
        string recipientName,
        string contractPath,
        List<string> annexPaths = null)
    {
        // Validate files
        if (!File.Exists(contractPath))
            return new SendResult { Success = false, Error = "Contract not found" };

        // Prepare file list
        var filePaths = new List<string> { contractPath };

        if (annexPaths != null)
        {
            foreach (var path in annexPaths)
            {
                if (File.Exists(path))
                    filePaths.Add(path);
            }
        }

        // Calculate total size
        long totalSize = 0;
        foreach (var path in filePaths)
        {
            totalSize += new FileInfo(path).Length;
        }

        // Check limit (2.5 GB)
        if (totalSize > 2.5 * 1024 * 1024 * 1024)
            return new SendResult { Success = false, Error = "Total size exceeds 2.5 GB" };

        // Create HTML message
        string htmlBody = $@"
            <h2>Hello {recipientName},</h2>
            <p>Please find attached your contract and related documents.</p>
            <p><strong>Attached documents:</strong></p>
            <ul>
                <li>{Path.GetFileName(contractPath)} (Main contract)</li>
                {string.Join("", annexPaths?.Select(p => $"<li>{Path.GetFileName(p)}</li>") ?? Array.Empty<string>())}
            </ul>
            <p>Please return the signed contract at your earliest convenience.</p>";

        // Configure arguments
        var recipients = new List<RecipientInfo>
        {
            new RecipientInfo { Email = recipientEmail }
        };

        Uri endpoint = new Uri("https://www.secure-exchanges.com/_api/0217/0217.asmx");

        var args = new MutliRecipientArgs(
            endpoint,
            _serial,
            _apiUser,
            _apiPassword,
            recipients,
            htmlBody,
            "Your Contract - Documents to Sign",
            password: null,
            filesList: null,
            SendMethodEnum.onlyEmail,
            sendByMyOwnSMTPServer: false,
            showSubject: true,
            getNotify: true,
            culture: "en-CA",
            maxOpeningTime: 10,
            expirationMinutes: 10080  // 7 days
        );

        // Attach files by path
        args.FilesPath = filePaths;

        // Send
        var response = MessageHelper.MultiRecipientMessage(args);

        if (response.Status == 200)
        {
            return new SendResult
            {
                Success = true,
                MessageUrl = response.RecipientsAnswer[0].Answer.URL,
                FileCount = filePaths.Count,
                TotalSize = totalSize
            };
        }

        return new SendResult
        {
            Success = false,
            Error = response.Data
        };
    }
}

public class SendResult
{
    public bool Success { get; set; }
    public string MessageUrl { get; set; }
    public string Error { get; set; }
    public int FileCount { get; set; }
    public long TotalSize { get; set; }
}

Method 2: Files in Memory (FileArgs)

Use this method when:

  • Files are generated dynamically
  • You're working with data streams
  • Files are not on disk

Quick Example

// Create FileArgs from in-memory data
var pdfBytes = File.ReadAllBytes(@"C:\temp\document.pdf");
var fileArgs = new FileArgs(pdfBytes, "document.pdf", "application/pdf");

var args = new MutliRecipientArgs(
    endpoint, serial, apiUser, apiPassword,
    recipients, message, subject,
    password: null,
    filesList: new List<FileArgs> { fileArgs },
    SendMethodEnum.onlyEmail,
    false, true, true, "en-CA", 5, 1440
);

Complete Example: PDF Report Generation

using System;
using System.Collections.Generic;
using System.IO;
using SecureExchangesSDK.Helpers;
using SecureExchangesSDK.Models.Args;
using SecureExchangesSDK.Models.Entity;
using SecureExchangesSDK.SecureExchanges;

public class ReportDeliveryService
{
    private readonly Guid _serial;
    private readonly Guid _apiUser;
    private readonly Guid _apiPassword;

    public ReportDeliveryService(Guid serial, Guid apiUser, Guid apiPassword)
    {
        _serial = serial;
        _apiUser = apiUser;
        _apiPassword = apiPassword;
    }

    /// <summary>
    /// Generates and sends a monthly report
    /// </summary>
    public SendResult SendMonthlyReport(
        string recipientEmail,
        string companyName,
        byte[] reportPdfBytes,
        byte[] dataExcelBytes = null)
    {
        // Prepare in-memory files
        var files = new List<FileArgs>
        {
            new FileArgs(
                reportPdfBytes,
                $"Report_{companyName}_{DateTime.Now:yyyy-MM}.pdf",
                "application/pdf"
            )
        };

        // Add Excel file if present
        if (dataExcelBytes != null && dataExcelBytes.Length > 0)
        {
            files.Add(new FileArgs(
                dataExcelBytes,
                $"Data_{companyName}_{DateTime.Now:yyyy-MM}.xlsx",
                "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
            ));
        }

        // HTML message
        string htmlBody = $@"
            <h2>Monthly Report - {companyName}</h2>
            <p>Please find attached your monthly report for {DateTime.Now:MMMM yyyy}.</p>
            <p>This report contains:</p>
            <ul>
                <li>Activity summary</li>
                <li>Performance indicators</li>
                {(dataExcelBytes != null ? "<li>Detailed data (Excel)</li>" : "")}
            </ul>
            <p>Please contact us if you have any questions.</p>";

        // Configuration
        var recipients = new List<RecipientInfo>
        {
            new RecipientInfo { Email = recipientEmail }
        };

        Uri endpoint = new Uri("https://www.secure-exchanges.com/_api/0217/0217.asmx");

        var args = new MutliRecipientArgs(
            endpoint,
            _serial,
            _apiUser,
            _apiPassword,
            recipients,
            htmlBody,
            $"Monthly Report {DateTime.Now:MMMM yyyy} - {companyName}",
            password: null,
            filesList: files,  // In-memory files
            SendMethodEnum.onlyEmail,
            sendByMyOwnSMTPServer: false,
            showSubject: true,
            getNotify: true,
            culture: "en-CA",
            maxOpeningTime: 5,
            expirationMinutes: 20160  // 14 days
        );

        var response = MessageHelper.MultiRecipientMessage(args);

        return new SendResult
        {
            Success = response.Status == 200,
            MessageUrl = response.Status == 200 ? response.RecipientsAnswer[0].Answer.URL : null,
            Error = response.Status != 200 ? response.Data : null
        };
    }
}

Common MIME Types

Extension MIME Type
.pdf application/pdf
.doc application/msword
.docx application/vnd.openxmlformats-officedocument.wordprocessingml.document
.xls application/vnd.ms-excel
.xlsx application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.png image/png
.jpg image/jpeg
.zip application/zip
.txt text/plain

Limits and Recommendations

Limit Value
Maximum total size 2.5 GB
Number of files Unlimited (within size limit)
File types All types accepted
Tip

For large files, use FilesPath rather than FileArgs to avoid loading the entire file into memory.

See Also