从asp.net核心网络api下载内存修改过的pptx文件

Question

我有一个pptx模板文件。我将文件加载到内存中，并使用openxml将pptx文件中的占位符替换为从数据库中获取的数据，然后下载该文件。这是我所做的，但这并没有下载它尝试一段时间的文件，然后显示“失败-网络错误”。

    [HttpGet]
    public async Task<IActionResult> Generate()
    {
        IDictionary<string, string> toReplace = new Dictionary<string, string>();
        toReplace.Add("Sample2", "Sample - Text!");
        toReplace.Add("Sample3", "Sample 3 - Text!");
        var filePath = @"C:\Users\TestUser\Downloads\TestFile.pptx";

        using (var templateFile = System.IO.File.Open(filePath, FileMode.Open, FileAccess.Read))
        {
            using (var memoryStream = new MemoryStream())
            {
                templateFile.CopyTo(memoryStream);                    
                using (PresentationDocument presentationDocument = PresentationDocument.Open(memoryStream, true))
                {
                    // Get the presentation part of the presentation document.
                    PresentationPart presentationPart = presentationDocument.PresentationPart;

                    // Verify that the presentation part and presentation exist.
                    if (presentationPart != null && presentationPart.Presentation != null)
                    {
                        // Get the Presentation object from the presentation part.
                        Presentation presentation = presentationPart.Presentation;

                        // Verify that the slide ID list exists.
                        if (presentation.SlideIdList != null)
                        {
                            foreach (var slideId in presentation.SlideIdList.Elements<SlideId>())
                            {
                                SlidePart slidePart = presentationPart.GetPartById(slideId.RelationshipId) as SlidePart;

                                ShapeTree tree = slidePart.Slide.CommonSlideData.ShapeTree;
                                foreach (DocumentFormat.OpenXml.Presentation.Shape shape in tree.Elements<DocumentFormat.OpenXml.Presentation.Shape>())
                                {
                                    // Run through all the paragraphs in the document
                                    foreach (Paragraph paragraph in shape.Descendants().OfType<Paragraph>())
                                    {
                                        foreach (Run run in paragraph.Elements<Run>())
                                        {
                                            foreach (var kvp in toReplace)
                                            {
                                                if (run.Text.InnerText.Contains(kvp.Key))
                                                {
                                                    run.Text = new DocumentFormat.OpenXml.Drawing.Text(kvp.Value);
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                    //presentationPart.Presentation.Save();
                }
                memoryStream.Seek(0, SeekOrigin.Begin);//scroll to stream start point
                MemoryStream memstr = new MemoryStream
                {
                    Position = 0
                };
                memoryStream.CopyTo(memstr);
                return File(memstr, System.Net.Mime.MediaTypeNames.Application.Octet, System.IO.Path.GetFileName(filePath));
            }
        }
    }

Answer 1

您在using块外使用memoryStream。尝试将其移到内部

using (var memoryStream = new MemoryStream())
{

   ...

   memoryStream.Seek(0, SeekOrigin.Begin);//scroll to stream start point
   MemoryStream memstr = new MemoryStream
   {
        Position = 0
   };
   memoryStream.CopyTo(memstr);
   return File(memstr, System.Net.Mime.MediaTypeNames.Application.Octet, System.IO.Path.GetFileName(filePath));
}

您实际上不需要在这里创建另一个MemoryStream对象