使用 MemoryStream 将 PDF 栅格化为图像

Updated: 2026年4月22日

如何使用 MemoryStream 将 PDF 页面转换为图像，而无需触及文件系统？

IronPDF 提供从 MemoryStream 加载 PDF 文档的功能。 (操作指南|API 参考)

使用PdfDocument.ToBitmap()方法将PDF页面导出为图像。这将返回一个 IronSoftware.Drawing.AnyBitmap 对象数组，可用于进一步处理。

using IronPdf;
using System.IO;

// Example rendering PDF documents to Images or Thumbnails
using var pdf = PdfDocument.FromFile("Example.pdf");

// Convert each page of the PDF document to a bitmap image
IronSoftware.Drawing.AnyBitmap[] pageImages = pdf.ToBitmap();

foreach (var bitmap in pageImages)
{
    // Use MemoryStream to handle the image data in memory
    using (MemoryStream memoryStream = new MemoryStream())
    {
        // Export the image to MemoryStream as a PNG format
        bitmap.ExportStream(memoryStream, IronSoftware.Drawing.AnyBitmap.ImageFormat.Png);
        
        // MemoryStream can now be used for further processing without touching the file system
        // Example: Send it over a network, save to a database, etc.
    }
    
    // Dispose of the bitmap once processing is complete to free resources
    bitmap.Dispose();
}

using IronPdf;
using System.IO;

// Example rendering PDF documents to Images or Thumbnails
using var pdf = PdfDocument.FromFile("Example.pdf");

// Convert each page of the PDF document to a bitmap image
IronSoftware.Drawing.AnyBitmap[] pageImages = pdf.ToBitmap();

foreach (var bitmap in pageImages)
{
    // Use MemoryStream to handle the image data in memory
    using (MemoryStream memoryStream = new MemoryStream())
    {
        // Export the image to MemoryStream as a PNG format
        bitmap.ExportStream(memoryStream, IronSoftware.Drawing.AnyBitmap.ImageFormat.Png);
        
        // MemoryStream can now be used for further processing without touching the file system
        // Example: Send it over a network, save to a database, etc.
    }
    
    // Dispose of the bitmap once processing is complete to free resources
    bitmap.Dispose();
}

Imports IronPdf
Imports System.IO

' Example rendering PDF documents to Images or Thumbnails
Using pdf = PdfDocument.FromFile("Example.pdf")

    ' Convert each page of the PDF document to a bitmap image
    Dim pageImages As IronSoftware.Drawing.AnyBitmap() = pdf.ToBitmap()

    For Each bitmap In pageImages
        ' Use MemoryStream to handle the image data in memory
        Using memoryStream As New MemoryStream()
            ' Export the image to MemoryStream as a PNG format
            bitmap.ExportStream(memoryStream, IronSoftware.Drawing.AnyBitmap.ImageFormat.Png)

            ' MemoryStream can now be used for further processing without touching the file system
            ' Example: Send it over a network, save to a database, etc.
        End Using

        ' Dispose of the bitmap once processing is complete to free resources
        bitmap.Dispose()
    Next
End Using

Imports IronPdf
Imports System.IO

' Example rendering PDF documents to Images or Thumbnails
Using pdf = PdfDocument.FromFile("Example.pdf")

    ' Convert each page of the PDF document to a bitmap image
    Dim pageImages As IronSoftware.Drawing.AnyBitmap() = pdf.ToBitmap()

    For Each bitmap In pageImages
        ' Use MemoryStream to handle the image data in memory
        Using memoryStream As New MemoryStream()
            ' Export the image to MemoryStream as a PNG format
            bitmap.ExportStream(memoryStream, IronSoftware.Drawing.AnyBitmap.ImageFormat.Png)

            ' MemoryStream can now be used for further processing without touching the file system
            ' Example: Send it over a network, save to a database, etc.
        End Using

        ' Dispose of the bitmap once processing is complete to free resources
        bitmap.Dispose()
    Next
End Using

以下是一个有用的 Stack Overflow 文章，以获取有关将位图保存到 MemoryStream 的更多信息。