当我尝试使用带有多个表的iTextSharp构建PDF文件时，出现以下错误消息：
无法访问已关闭的流。
这是我的代码：
//Create a byte array that will eventually hold our final PDF
Byte[] bytes;
List<TableObject> myTables = getTables();
TableObject currentTable = new TableObject();
//Boilerplate iTextSharp setup here
//Create a stream that we can write to, in this case a MemoryStream
using (MemoryStream ms = new MemoryStream())
{
//Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
using (Document doc = new Document(PageSize.A4, 10f, 10f, 10f, 0f))
{
foreach (TableObject to in myTables)
{
//Create a writer that's bound to our PDF abstraction and our stream
using (PdfWriter writer = PdfWriter.GetInstance(doc, ms))
{
if (!doc.IsOpen())
{
//Open the document for writing
doc.Open();
}
//Get the data from database corresponding to the current tableobject and fill all the stuff we need!
DataTable dt = getDTFromID(to._tableID);
Object[] genObjects = new Object[5];
genObjects = gen.generateTable(dt, currentTable._tableName, currentTable._tableID.ToString(), currentTable, true);
StringBuilder sb = (StringBuilder)genObjects[1];
String tableName = sb.ToString();
Table myGenTable = (Table)genObjects[0];
String table = genObjects[2].ToString();
using (StringReader srHtml = new StringReader(table))
{
//Parse the HTMLiTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, srHtml);
}
//should give empty page at the end, need to fix it later
doc.NewPage();
}
}
doc.Close();
}
//After all of the PDF "stuff" above is done and closed but **before** we
//close the MemoryStream, grab all of the active bytes from the stream
bytes = ms.ToArray();
}
//Now we just need to do something with those bytes.
Response.ContentType = "application/pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=Report_complete.pdf");
Response.BinaryWrite(bytes);
这是我的asp.net应用程序中的完整堆栈跟踪：
[ObjectDisposedException：无法访问已关闭的流。]
System.IO .__ Error.StreamIsClosed（）+57
System.IO.MemoryStream.Write（Byte []缓冲区，Int32偏移量，Int32计数） +11011171 iTextSharp.text.pdf.OutputStreamCounter.Write（Byte [] buffer，Int32 offset，Int32 count）+52
iTextSharp.text.pdf.PdfIndirectObject.WriteTo（Stream os）+53
iTextSharp.text.pdf.PdfBody.Write（PdfIndirectObject indirect，Int32 refNumber，Int32代）+100
iTextSharp.text.pdf.PdfBody.Add（PdfObject objecta，Int32 refNumber， Int32代，布尔inObjStm）+385
iTextSharp.text.pdf.PdfWriter.AddToBody（PdfObject objecta， PdfIndirectReference refa）+51
iTextSharp.text.pdf.Type1Font.WriteFont（PdfWriter writer， PdfIndirectReference piref，Object [] parms）+317
iTextSharp.text.pdf.FontDetails.WriteFont（PdfWriter writer）+296
iTextSharp.text.pdf.PdfWriter.AddSharedObjectsToBody（）+180
iTextSharp.text.pdf.PdfWriter.Close（）+86
iTextSharp.text.DocWriter.Dispose（）+10
System.Web.Util.CalliEventHandlerDelegateProxy.Callback（Object sender， EventArgs e）+51 System.Web.UI.Control.OnLoad（EventArgs e）+92
System.Web.UI.Control.LoadRecursive（）+54
System.Web.UI.Page.ProcessRequestMain（布尔 includeStagesBeforeAsyncPoint，Boolean includeStagesAfterAsyncPoint） 772
bytes - 数组应该可以在using语句中访问，但看起来有错误。
我尝试在foreach块中移动using(writer ...)循环：
//Create a byte array that will eventually hold our final PDF
//must be outside of the foreach loop (and everything else), because we store every single generated table in here for the final pdf!!
Byte[] bytes;
List<TableObject> myTables = getTables();
TableObject currentTable = new TableObject();
//Boilerplate iTextSharp setup here
//Create a stream that we can write to, in this case a MemoryStream
using (MemoryStream ms = new MemoryStream())
{
//Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
using (Document doc = new Document(PageSize.A4, 10f, 10f, 10f, 0f))
{
//Create a writer that's bound to our PDF abstraction and our stream
using (PdfWriter writer = PdfWriter.GetInstance(doc, ms))
{
//loop all tableobjects inside the document & the instance of PDFWriter itself!
foreach (TableObject to in myTables)
{
//only happens on the first run!
if (!doc.IsOpen())
{
//Open the document for writing
doc.Open();
}
//Get the data from database corresponding to the current tableobject and fill all the stuff we need!
DataTable dt = getDTFromID(to._tableID);
Object[] genObjects = new Object[5];
genObjects = gen.generateTable(dt, currentTable._tableName, currentTable._tableID.ToString(), currentTable, true);
StringBuilder sb = (StringBuilder)genObjects[1];
String tableName = sb.ToString();
Table myGenTable = (Table)genObjects[0];
String table = genObjects[2].ToString();
using (StringReader srHtml = new StringReader(table))
{
//Parse the HTML
iTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, srHtml);
}
//this will probably render a whole new page at the end of the file!! need to be fixed later!!!
doc.NewPage();
}
//After all of the PDF "stuff" above is done and closed but **before** we
//close the MemoryStream, grab all of the active bytes from the stream
bytes = ms.ToArray();
}
doc.Close();
}
}
//Now we just need to do something with those bytes.
Response.ContentType = "application/pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=ShiftReport_complete.pdf");
Response.BinaryWrite(bytes);
但我仍然得到同样的错误。
答案 0 :(得分：14)
PdfWriter默认关闭流。只需在PdfWriter.GetInstance
之后添加以下行 protected void onCreate(Bundle savedInstanceState)
{
EditText etDateF,etDateT,etLocation,etFormNo,etVIN,etEngine,etName;
Button btSearch;
LinearLayout liBottom;
static int iState = 0; // 1=complaint;2=failure
String[][] saData = null;
super.onCreate(savedInstanceState);
methods = new gtCommanMethods(this);
tableMaster = new TableMaster(this);
Display display= ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
bConstants.SCR_WIDTH = display.getWidth();
bConstants.SCR_HEIGHT = display.getHeight();
LinearLayout liMain = new LinearLayout(this);
liMain.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT));
liMain.setOrientation(LinearLayout.VERTICAL);
etDateF = new EditText(this);
etDateT = new EditText(this);
etLocation = new EditText(this);
etFormNo = new EditText(this);
etVIN = new EditText(this);
etEngine = new EditText(this);
etName = new EditText(this);
etDateF.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etDateT.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etLocation.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etFormNo.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etVIN.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etEngine.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
etName.setLayoutParams(new LinearLayout.LayoutParams(150, LinearLayout.LayoutParams.WRAP_CONTENT));
String search = getResources().getString(R.string.search);
btSearch = new Button(this);
btSearch.setText(search);
btSearch.setBackgroundResource(R.drawable.green_patch);
LinearLayout li1 = new LinearLayout(this);
li1.setOrientation(LinearLayout.HORIZONTAL);
li1.addView(new custText(this, getResources().getString(R.string.from_date)));
li1.addView(etDateF);
li1.addView(new custText(this, getResources().getString(R.string.to_date)));
li1.addView(etDateT);
LinearLayout li3 = new LinearLayout(this);
li3.setOrientation(LinearLayout.HORIZONTAL);
li3.addView(new custText(this, getResources().getString(R.string.location)));
li3.addView(etLocation);
if(iState == 1)
li3.addView(new custText(this, getResources().getString(R.string.complaint_no)));
else if(iState == 2)
li3.addView(new custText(this, getResources().getString(R.string.failure_no)));
li3.addView(etFormNo);
LinearLayout li5 = new LinearLayout(this);
li5.setOrientation(LinearLayout.HORIZONTAL);
li5.addView(new custText(this, getResources().getString(R.string.vin)));
li5.addView(etVIN);
li5.addView(new custText(this, getResources().getString(R.string.eng_no)));
li5.addView(etEngine);
LinearLayout li7 = new LinearLayout(this);
li7.setOrientation(LinearLayout.HORIZONTAL);
li7.addView(new custText(this, getResources().getString(R.string.name)));
li7.addView(etName);
li7.addView(btSearch);
LinearLayout liUpper = new LinearLayout(this);
liUpper.setOrientation(LinearLayout.VERTICAL);
liUpper.addView(li1);
liUpper.addView(li3);
liUpper.addView(li5);
liUpper.addView(li7);
liBottom = new LinearLayout(this);
liBottom.setOrientation(LinearLayout.VERTICAL);
LinearLayout liTableHeader = new LinearLayout(this);
liTableHeader.setOrientation(LinearLayout.HORIZONTAL);
liTableHeader.setBackgroundColor(Color.LTGRAY);
liTableHeader.setPadding(0, 5, 0, 5);
liTableHeader.addView(new custText(this,getResources().getString(R.string.name),true),new LinearLayout.LayoutParams(bConstants.SCR_WIDTH/3, LinearLayout.LayoutParams.WRAP_CONTENT));
liTableHeader.addView(new custText(this, getResources().getString(R.string.phone_no),true),new LinearLayout.LayoutParams(bConstants.SCR_WIDTH/3, LinearLayout.LayoutParams.WRAP_CONTENT));
liTableHeader.addView(new custText(this, getResources().getString(R.string.frame_vin_no),true),new LinearLayout.LayoutParams(bConstants.SCR_WIDTH/3, LinearLayout.LayoutParams.WRAP_CONTENT));
liMain.addView(liUpper,new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
liMain.addView(liTableHeader,new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
liMain.addView(liBottom,new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
setContentView(liMain);}
答案 1 :(得分：1)
解决方案很简单，只需在.ToList()循环中将foreach放到我的集合中：
foreach (TableObject to in myTables.ToList())
{
//some code stuff
this question帮助我解决了这个问题。
答案 2 :(得分：0)
using PdfWriter writer..阻止ms阻止基础流writer尝试处置PdfWriter writer的可能性。
尝试在没有using阻止的情况下使用getch删除并查看。它应该解决这个问题。
答案 3 :(得分：0)
using命令会导致您的MemoryStream被释放，因此当您访问它时，托管和非托管资源已经被释放。将此代码放在foreach循环的结束括号之后：
ParseQuery<Article> query = new ParseQuery<Article>();
if (souCategorie.SelectedIndex >= 0)
{
query.WhereEqualTo("idSCategorie", listeSouCategorie.ElementAt(souCategorie.SelectedIndex));
}
if(motcle.Text.Length > 0)
{
query.WhereContains("nom", motcle.Text);
// query.WhereContains("description", motcle.Text);
}
if(distance.Text.Length>0)
if (Convert.ToDouble(distance.Text) > 0)
{
Debug.WriteLine(distance.Text);
ParseGeoPoint geo = new ParseGeoPoint();
geo.Latitude = geoposition.Coordinate.Latitude;
geo.Longitude = geoposition.Coordinate.Longitude;
query.WhereWithinDistance("coordonnees", geo, ParseGeoDistance.FromKilometers(Convert.ToDouble(distance.Text)));
}
IEnumerable<Article> lst = await query.FindAsync();
rechercheResult.DataContext = lst.ToList();
答案 4 :(得分：0)
该问题似乎是由于在关闭文档之前已处置PdfWriter。在PdfWriter的using语句中调用doc.Close()应该可以解决问题。