使用 MemoryStream 將 PDF 轉為圖像

Curtis Chau

更新:2026年4月21日

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如何使用 MemoryStream 將 PDF 頁面轉換為圖片，且不需接觸檔案系統？

IronPDF 支援從 MemoryStream 載入 PDF 文件。 (操作指南 | API 參考)

使用 PdfDocument.ToBitmap() 方法將 PDF 頁面匯出為圖片。這將返回一個 IronSoftware.Drawing.AnyBitmap 物件的陣列，可用於後續處理。

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
Private pdf = PdfDocument.FromFile("Example.pdf")

' Convert each page of the PDF document to a bitmap image
Private 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 bitmap

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以下是一篇來自 Stack Overflow 的實用文章，提供將位圖儲存至 MemoryStream 的詳細說明。