使用 MemoryStream 將 PDF 光柵化為圖像

Updated: 2026年4月22日

如何使用 MemoryStream 將 PDF 頁面轉換為圖像，而不接觸文件系統？

IronPDF 提供從 MemoryStream 載入 PDF 文件的功能。 (How-Tos | API Reference) using PdfDocument.ToBitmap() 方法將 PDF 頁面導出為圖像。這將返回一個 IronSoftware.Drawing.AnyBitmap 物件陣列，可用於進一步處理。

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

這裡有一篇有用的 Stack Overflow 文章，提供有關將位圖保存到 MemoryStream 的更多詳細資訊。