无法在 C# 中加载 pdf 文档

Question

嗨，这是我的 C# 代码：

Byte[] bytes;

int orderID = Convert.ToInt32(e.CommandArgument);

var templateData = ordersBL.GetTemplateDetails(orderID);

using (MemoryStream ms = new MemoryStream())
{

using (Document document = new Document(PageSize.A4, 10, 10, 10, 10))
{
PdfWriter writer = PdfWriter.GetInstance(document, ms);
foreach (var temp in templateData.ToList())
{

string message = temp.Message;
string tempimage = Convert.ToBase64String(temp.logo);
string base64 = tempimage;
byte[] imageBytes = Convert.FromBase64String(base64);
iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(imageBytes);
if (image.Height > image.Width)
{
float percentage = 0.0f;
percentage = 700 / image.Height;
image.ScalePercent(percentage * 100);
}
else

{

float percentage = 0.0f;
percentage = 140 / image.Width;
image.ScalePercent(percentage * 100);
}

if (!document.IsOpen())
{

document.Open();
}
document.Add(image);
using (var htmlWorker = new HTMLWorker(document))
{

using (var sr = new StringReader(message))
{


htmlWorker.Parse(sr);
}
}
Paragraph paragraph = new Paragraph();
paragraph.SpacingBefore = 10;
paragraph.SpacingAfter = 10;
paragraph.Alignment = Element.ALIGN_LEFT;
// paragraph.Font = FontFactory.GetFont(FontFactory.HELVETICA, 12f, BaseColor.GREEN);

document.Add(paragraph);
document.NewPage();
}
bytes = ms.ToArray();
document.Close();

}
}
Response.ContentType = "application/pdf";
string pdfName = "User";
Response.AddHeader("Content-Disposition", "attachment; filename=" + pdfName + ".pdf");
Response.Buffer = true;
Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
Response.BinaryWrite(bytes);
Response.End();
Response.Close();
Response.Flush();
}

PDF已下载，但显示加载pdf文档失败。

在c#中加载pdf文档失败

我没有找到我在代码中出错的地方。

请给我正确的代码

谢谢。

Answer 1

您没有创建完整的 PDF 文件。请看我对问题的回答Trying to get a memory stream from a pdfstamper into a pdfreader but getting: "PDF startxref not found"

当您关闭 PDF 文档时，它就完成了：

document.Close();

在您执行此操作之前PDF 不完整。

但是，您在关闭文档之前询问MemoryStream：

bytes = ms.ToArray();
document.Close();

这意味着bytes 不包含完整的 PDF。

此外，您使用的是HTMLWorker。那个班多年前就被废弃了，请看documentation about XML Worker的介绍。

HTMLWorker 可能会隐式关闭 document 对象（我不记得了，正如我所说：HTMLWorker 不再使用）。在这种情况下，将paragraph 对象添加到文档的代码将引发异常，说明文档已关闭并且您不能再添加任何额外内容。

Answer 2

@shivakumar，请尝试喜欢这个示例并根据您的数据进行更改。

Byte[] bytes = ImageToByteArray(System.Drawing.Image.FromFile(@"D:\Test\Sample1.png"));
         //Converted Image to byte[] 

        using (MemoryStream ms = new MemoryStream())
        {
            Document document = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            PdfWriter.GetInstance(document, Response.OutputStream);
            document.Open();     
            byte[] imageBytes = bytes;
            ms.Write(bytes, 0, bytes.Length);
            iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(imageBytes);
            if (image.Height > image.Width)
            {
                float percentage = 0.0f;
                percentage = 700 / image.Height;
                image.ScalePercent(percentage * 100);
            }
            else
            {

                float percentage = 0.0f;
                percentage = 140 / image.Width;
                image.ScalePercent(percentage * 100);
            }

            if (!document.IsOpen())
            {

                document.Open();
            }
            document.Add(image);
            var htmlWorker = new HTMLWorker(document);
            string message="hi";
            using (var sr = new StringReader(message))
            {


                htmlWorker.Parse(sr);
            }

            bytes = ms.ToArray();
            document.Close();
        }
        Response.ContentType = "application/pdf";
        string pdfName = "User";
        Response.AddHeader("Content-Disposition", "attachment; filename=" + pdfName + ".pdf");
        Response.Buffer = true;
        Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
        Response.BinaryWrite(bytes);
        Response.End();
        Response.Close();
        Response.Flush();

Answer 3

如果您有一个包含 PDF 的有效流，并且您从 Chrome 收到“加载 PDF 文档失败”，这肯定会导致问题：

Response.AddHeader("Content-Disposition", "attachment; filename=" + pdfName + ".pdf");

'attachment' 专门告诉浏览器不在浏览器中显示这个文件，而是直接发送文件。我花了几个小时才了解到 Chrome 的 PDF 查看器在这种情况下会卡住，这可能是设计使然！

试试这个：

Response.AddHeader("Content-Disposition", "inline; filename=" + pdfName + ".pdf");

更多：Content-Disposition:What are the differences between "inline" and "attachment"?