如何在 .NET 中将 PDF 转换为图像

using IronPdf;

var renderer = new ChromePdfRenderer();

string htmlContent = """
    <h1>Order Confirmation</h1>
    <p>Thank you for your purchase.</p>
    <table>
        <tr><th>Item</th><th>Qty</th><th>Price</th></tr>
        <tr><td>Widget A</td><td>2</td><td>$19.99</td></tr>
        <tr><td>Widget B</td><td>1</td><td>$59.99</td></tr>
    </table>
    <p><strong>Order Total: $99.97</strong></p>
    """;

PdfDocument pdf = renderer.RenderHtmlAsPdf(htmlContent);

// pdf.BinaryData holds the complete PDF as a byte array
byte[] pdfBytes = pdf.BinaryData;
Console.WriteLine($"PDF generated: {pdfBytes.Length} bytes");

Imports IronPdf

Dim renderer As New ChromePdfRenderer()

Dim htmlContent As String = "
    <h1>Order Confirmation</h1>
    <p>Thank you for your purchase.</p>
    <table>
        <tr><th>Item</th><th>Qty</th><th>Price</th></tr>
        <tr><td>Widget A</td><td>2</td><td>$19.99</td></tr>
        <tr><td>Widget B</td><td>1</td><td>$59.99</td></tr>
    </table>
    <p><strong>Order Total: $99.97</strong></p>
    "

Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf(htmlContent)

' pdf.BinaryData holds the complete PDF as a byte array
Dim pdfBytes As Byte() = pdf.BinaryData
Console.WriteLine($"PDF generated: {pdfBytes.Length} bytes")

using IronPdf;
using MailKit.Net.Smtp;
using MailKit.Security;
using MimeKit;

// Step 1 -- generate the PDF in memory
var renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Monthly Report</h1><p>Generated automatically.</p>");

// Step 2 -- build the email message
var message = new MimeMessage();
message.From.Add(new MailboxAddress("Reports Service", "reports@example.com"));
message.To.Add(new MailboxAddress("Alice Smith", "alice@example.com"));
message.Subject = "Your Monthly Report is Ready";

var builder = new BodyBuilder();
builder.TextBody = "Hello Alice,\n\nPlease find your monthly report attached.\n\nRegards,\nReports Service";
builder.HtmlBody = "<p>Hello Alice,</p><p>Please find your monthly report attached.</p>";

// Add the in-memory PDF as an attachment
builder.Attachments.Add("MonthlyReport.pdf", pdf.BinaryData, new ContentType("application", "pdf"));
message.Body = builder.ToMessageBody();

// Step 3 -- send via SMTP with TLS
using var client = new SmtpClient();
await client.ConnectAsync("smtp.example.com", 587, SecureSocketOptions.StartTls);
await client.AuthenticateAsync("username", "app-password");
await client.SendAsync(message);
await client.DisconnectAsync(true);

Imports IronPdf
Imports MailKit.Net.Smtp
Imports MailKit.Security
Imports MimeKit

' Step 1 -- generate the PDF in memory
Dim renderer As New ChromePdfRenderer()
Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf("<h1>Monthly Report</h1><p>Generated automatically.</p>")

' Step 2 -- build the email message
Dim message As New MimeMessage()
message.From.Add(New MailboxAddress("Reports Service", "reports@example.com"))
message.To.Add(New MailboxAddress("Alice Smith", "alice@example.com"))
message.Subject = "Your Monthly Report is Ready"

Dim builder As New BodyBuilder()
builder.TextBody = "Hello Alice," & vbCrLf & vbCrLf & "Please find your monthly report attached." & vbCrLf & vbCrLf & "Regards," & vbCrLf & "Reports Service"
builder.HtmlBody = "<p>Hello Alice,</p><p>Please find your monthly report attached.</p>"

' Add the in-memory PDF as an attachment
builder.Attachments.Add("MonthlyReport.pdf", pdf.BinaryData, New ContentType("application", "pdf"))
message.Body = builder.ToMessageBody()

' Step 3 -- send via SMTP with TLS
Using client As New SmtpClient()
    Await client.ConnectAsync("smtp.example.com", 587, SecureSocketOptions.StartTls)
    Await client.AuthenticateAsync("username", "app-password")
    Await client.SendAsync(message)
    Await client.DisconnectAsync(True)
End Using

using IronPdf;
using System.Net;
using System.Net.Mail;

// Generate the PDF
var renderer = new ChromePdfRenderer();
PdfDocument pdf = renderer.RenderHtmlAsPdf("<h1>Invoice #1001</h1><p>Amount due: $350.00</p>");

// Build the mail message
using var message = new MailMessage("invoices@example.com", "customer@example.com");
message.Subject = "Invoice #1001 Attached";
message.Body    = "Your invoice is attached to this email. Please remit payment within 30 days.";
message.IsBodyHtml = false;

// Wrap the byte array in a MemoryStream for the Attachment constructor
var stream = new MemoryStream(pdf.BinaryData);
message.Attachments.Add(new Attachment(stream, "Invoice-1001.pdf", "application/pdf"));

// Send via SMTP
using var client = new SmtpClient("smtp.example.com", 587)
{
    Credentials = new NetworkCredential("username", "password"),
    EnableSsl   = true
};
await client.SendMailAsync(message);

Imports IronPdf
Imports System.Net
Imports System.Net.Mail
Imports System.IO

' Generate the PDF
Dim renderer As New ChromePdfRenderer()
Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf("<h1>Invoice #1001</h1><p>Amount due: $350.00</p>")

' Build the mail message
Using message As New MailMessage("invoices@example.com", "customer@example.com")
    message.Subject = "Invoice #1001 Attached"
    message.Body = "Your invoice is attached to this email. Please remit payment within 30 days."
    message.IsBodyHtml = False

    ' Wrap the byte array in a MemoryStream for the Attachment constructor
    Dim stream As New MemoryStream(pdf.BinaryData)
    message.Attachments.Add(New Attachment(stream, "Invoice-1001.pdf", "application/pdf"))

    ' Send via SMTP
    Using client As New SmtpClient("smtp.example.com", 587)
        client.Credentials = New NetworkCredential("username", "password")
        client.EnableSsl = True
        Await client.SendMailAsync(message)
    End Using
End Using

using IronPdf;
using MailKit.Net.Smtp;
using MailKit.Security;
using MimeKit;
using Microsoft.Extensions.Logging;

async Task SendPdfEmailWithRetryAsync(
    byte[] pdfBytes,
    string recipientEmail,
    string subject,
    ILogger logger,
    int maxAttempts = 3)
{
    for (int attempt = 1; attempt <= maxAttempts; attempt++)
    {
        try
        {
            var message = new MimeMessage();
            message.From.Add(new MailboxAddress("Mailer", "mailer@example.com"));
            message.To.Add(MailboxAddress.Parse(recipientEmail));
            message.Subject = subject;

            var builder = new BodyBuilder { TextBody = "Your document is attached." };
            builder.Attachments.Add("document.pdf", pdfBytes, new ContentType("application", "pdf"));
            message.Body = builder.ToMessageBody();

            using var smtpClient = new SmtpClient();
            await smtpClient.ConnectAsync("smtp.example.com", 587, SecureSocketOptions.StartTls);
            await smtpClient.AuthenticateAsync("user", "pass");
            await smtpClient.SendAsync(message);
            await smtpClient.DisconnectAsync(true);

            logger.LogInformation("Email sent to {Email} on attempt {Attempt}", recipientEmail, attempt);
            return;
        }
        catch (Exception ex) when (attempt < maxAttempts)
        {
            logger.LogWarning(ex, "Send attempt {Attempt} failed. Retrying...", attempt);
            await Task.Delay(TimeSpan.FromSeconds(Math.Pow(2, attempt)));
        }
    }
}

Imports IronPdf
Imports MailKit.Net.Smtp
Imports MailKit.Security
Imports MimeKit
Imports Microsoft.Extensions.Logging

Public Async Function SendPdfEmailWithRetryAsync(
    pdfBytes As Byte(),
    recipientEmail As String,
    subject As String,
    logger As ILogger,
    Optional maxAttempts As Integer = 3) As Task

    For attempt As Integer = 1 To maxAttempts
        Try
            Dim message = New MimeMessage()
            message.From.Add(New MailboxAddress("Mailer", "mailer@example.com"))
            message.To.Add(MailboxAddress.Parse(recipientEmail))
            message.Subject = subject

            Dim builder = New BodyBuilder With {
                .TextBody = "Your document is attached."
            }
            builder.Attachments.Add("document.pdf", pdfBytes, New ContentType("application", "pdf"))
            message.Body = builder.ToMessageBody()

            Using smtpClient = New SmtpClient()
                Await smtpClient.ConnectAsync("smtp.example.com", 587, SecureSocketOptions.StartTls)
                Await smtpClient.AuthenticateAsync("user", "pass")
                Await smtpClient.SendAsync(message)
                Await smtpClient.DisconnectAsync(True)
            End Using

            logger.LogInformation("Email sent to {Email} on attempt {Attempt}", recipientEmail, attempt)
            Return
        Catch ex As Exception When attempt < maxAttempts
            logger.LogWarning(ex, "Send attempt {Attempt} failed. Retrying...", attempt)
            Await Task.Delay(TimeSpan.FromSeconds(Math.Pow(2, attempt)))
        End Try
    Next
End Function

PdfDocument pdf;
try
{
    pdf = renderer.RenderHtmlAsPdf(htmlContent);
}
catch (IronPdf.Exceptions.PdfException ex)
{
    logger.LogError(ex, "PDF rendering failed");
    throw;
}

Imports IronPdf.Exceptions

Dim pdf As PdfDocument
Try
    pdf = renderer.RenderHtmlAsPdf(htmlContent)
Catch ex As PdfException
    logger.LogError(ex, "PDF rendering failed")
    Throw
End Try

pdf.CompressImages(60); // quality 0-100
byte[] compressedPdfBytes = pdf.BinaryData;

pdf.CompressImages(60) ' quality 0-100
Dim compressedPdfBytes As Byte() = pdf.BinaryData