如何使用带有C＃的ASP.NET在PDF中截取图像？

我想使用带有C＃的asp.net在PDF中截取图像。我使用adobe acrobat pro开发了一个PDF。我需要从pdf中获取图像作为屏幕截图左右，并使用c＃将此图像转换为二进制（base 64）文件。

我可以在代码部分正在运行的情况下拍摄页面的屏幕截图。但无法在PDF文件中获取图像的屏幕截图



我尝试过：

I want to take screenshot of image in a PDF using asp.net with C#. I have developed a PDF using adobe acrobat pro. I need to get the Image from the pdf as a screen shot or so and convert this image to a binary (base 64) file using c# .
I am able to take the screen shot of the page with the code part is running. But the unable to get the screen shot of a image in a PDF File

What I have tried:

public static void Capture(string CapturedFilePath)
      {
          Bitmap bitmap = new Bitmap
        (Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);

          Graphics graphics = Graphics.FromImage(bitmap as System.Drawing.Image);
          graphics.CopyFromScreen(25, 25, 25, 25, bitmap.Size);

          bitmap.Save(CapturedFilePath, ImageFormat.Bmp);
      }