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()的时候碰到了如下错误：
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？从错误我可以知道我们准备操作的Stream已经关闭，这是因为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有个熟悉就是让我们设置是否自动关闭Stream的，而默认是关闭的。
