假设有这么一段代码：
private
void
CreatePdf()
{ Document doc=new Document(); MemoryStream ms=new MemoryStream(); PdfWriter writer =PdfWriter.GetInstance(doc,ms); doc.Open(); doc.Add(new Paragraph(DateTime.Now.ToLongDateString())); doc.Close(); ViewPdf(ms); }
private
void
ViewPdf(Stream fs)
{ byte[] buffer=new byte[fs.Length]; fs.Position=0; fs.Read(buffer,0,(int)fs.Length); Response.Clear(); Response.ContentType = "application/pdf"; Response.BinaryWrite(buffer); Response.OutputStream.Flush(); Response.OutputStream.Close(); }
在调用CreatePdf()的时候碰到了以下错误：
Cannot access a closed Stream.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.Exception Details: System.ObjectDisposedException: Cannot access a closed Stream.
Source Error:
Line 58: private void ViewPdf(Stream fs)
Line 59: {
Line 60: byte[] buffer=new byte[fs.Length]; Line 61: fs.Position=0;
Line 62: fs.Read(buffer,0,(int)fs.Length); |
问题出在哪里了呢？从错误我能够知道咱们准备操做的Stream已经关闭，这是由于iTextSharp自动关闭生成的Stream了，那有没有办法不关闭呢？
看了下面这段代码，也许就不用我说什么了：
private
void
Page_Load(
object
sender, System.EventArgs e)
{ //CreatePdf(); EditPDF(); }
private
void
EditPDF()
{ PdfReader reader =new PdfReader(@"e:\xml2PDF.pdf"); MemoryStream ms=new MemoryStream(); PdfStamper stamper=new PdfStamper(reader,ms); stamper.Writer.CloseStream=false; PdfContentByte cb=stamper.GetOverContent(1); cb.Circle(250,250,50); cb.SetColorFill(iTextSharp.text.Color.RED); cb.SetColorStroke(iTextSharp.text.Color.WHITE); cb.FillStroke(); stamper.Close(); ViewPdf(ms); }
private
void
CreatePdf()
{ Document doc=new Document(); MemoryStream ms=new MemoryStream(); PdfWriter writer =PdfWriter.GetInstance(doc,ms); writer.CloseStream=false; doc.Open(); doc.Add(new Paragraph(DateTime.Now.ToLongDateString())); doc.Close(); ViewPdf(ms); }
private
void
ViewPdf(Stream fs)
{ byte[] buffer=new byte[fs.Length]; fs.Position=0; fs.Read(buffer,0,(int)fs.Length); fs.Close(); Response.Clear(); Response.ContentType = "application/pdf"; Response.BinaryWrite(buffer); Response.OutputStream.Flush(); Response.OutputStream.Close(); }
原来PdfWriter有个熟悉就是让咱们设置是否自动关闭Stream的，而默认是关闭的。
2006-12-01更新ViewPdf function
private
void
ViewPdf(Stream fs)
{
byte [] buffer = new byte [fs.Length];
fs.Position = 0 ;
fs.Read(buffer, 0 , ( int )fs.Length);
Response.Clear();
// Response.AddHeader("Content-Disposition", "attachment;FileName=out.pdf");
Response.AddHeader( " Content-Length " ,fs.Length.ToString());
Response.ContentType = " application/pdf " ;
fs.Close();
Response.BinaryWrite(buffer);
Response.OutputStream.Flush();
Response.OutputStream.Close();
}
若是须要下载而不是在IE中看的话，请把Response.AddHeader("Content-Disposition", "attachment;FileName=out.pdf");前的注释去掉，并替换上你想要的名字。
{
byte [] buffer = new byte [fs.Length];
fs.Position = 0 ;
fs.Read(buffer, 0 , ( int )fs.Length);
Response.Clear();
// Response.AddHeader("Content-Disposition", "attachment;FileName=out.pdf");
Response.AddHeader( " Content-Length " ,fs.Length.ToString());
Response.ContentType = " application/pdf " ;
fs.Close();
Response.BinaryWrite(buffer);
Response.OutputStream.Flush();
Response.OutputStream.Close();
}
若是不指定 Response.AddHeader( " Content-Length " ,fs.Length.ToString());，IE会把网页内容也输出，在PDF后面，此时显示生成的PDF被破坏（这个说是IE的一个bug，我也不清楚）
若是附件名为中文：
Response.AddHeader("Content-Disposition", "attachment;FileName="+HttpUtility.UrlEncode("中文.pdf"));
内嵌显示PDF
Response.AddHeader("Content-Disposition", "inline;FileName=out.pdf");
更多这方面的信息google上搜索吧。
另一个和缓存有关的信息，Cache-Control，须要的本身研究下吧。