在MigraDoc-WPF中使用section.AddImage()后释放锁定图像文件

Question

我有以下代码生成报告PDF,上传它然后删除生成中使用的临时图像:

// Generate document and then add a section with an image
var document = new Document {Info = {Title = "Results"}};
var section = document.AddSection();
var logo = section.AddImage(logoPath);

// Render the PDF
const PdfFontEmbedding embedding = PdfFontEmbedding.Always;
PdfDocumentRenderer pdfRenderer = new PdfDocumentRenderer(unicode, embedding);
pdfRenderer.Document = document;
pdfRenderer.RenderDocument(); // This is the line which locks the files

// Save the PDF to a memory stream and upload it to azure blob storage
var reportPath = "";
using (var stream = new MemoryStream())
{
    pdfRenderer.Save(stream, false);
    reportPath = UploadBlob("reports", "Report.pdf", stream);
}

// Delete the local copy of the logo - this is where the exception occurs
Directory.Delete(Directory.GetParent(logoPath).ToString(), true);

当我尝试删除图像的目录时,会引发以下异常:

 An exception of type 'System.IO.IOException' occurred in mscorlib.dll but was not handled in user code

 Additional information: The process cannot access the file 'Capture.PNG' because it is being used by another process.

我已经通过代码进行了调试,以确保在调用pdfRenderer.RenderDocument()之前可以访问该文件,如代码注释中所述.

PdfDocumentRenderer类没有close或dispose方法,它没有实现IDisposable,所以我不能使用using块.

如何释放文件上的锁？

Answer 1

我修复了修改PdfSharp.Drawing\XImage.cs的"BitmapImage锁定文件"错误,如下所示:替换第114行:

  this.wpfImage = new BitmapImage(new Uri(path));  // AGHACK

同

  BitmapImage imgTemp = new BitmapImage();
  imgTemp.BeginInit();
  imgTemp.CacheOption = BitmapCacheOption.OnLoad;
  imgTemp.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
  imgTemp.UriSource = new Uri(path);
  imgTemp.EndInit();
  this.wpfImage = imgTemp;

它对我有用.