iTextSharp 合并PDF后，无法删除已经合并的单个文件

 private void MergePDFFiles(string[] fileList, string outMergeFile)
        {
            List<PdfReader> readerList = new List<PdfReader>();//记录合并PDF集合
            iTextSharp.text.Document document = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4.Rotate());
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(outMergeFile, FileMode.Create));
            document.Open();  

            PdfContentByte cb = writer.DirectContent;
            PdfImportedPage newPage;
            for (int i = 0; i < fileList.Length; i++)
            {
                if (!string.IsNullOrEmpty(fileList[i]))
                {
                    PdfReader reader = new PdfReader(fileList[i]);
                    int iPageNum = reader.NumberOfPages;
                    for (int j = 1; j <= iPageNum; j++)
                    {
                        document.NewPage();
                        newPage = writer.GetImportedPage(reader, j);
                        cb.AddTemplate(newPage, 0, 0);
                    }
                    readerList.Add(reader);
                }
            }
            document.Close();

1             foreach (var rd in readerList)
2             {
3                 rd.Dispose();
4             }  

原文链接：http://blog.csdn.net/hebbers/article/details/70332015 关键点在与

PdfReader的循环释放，定义局部变量后独立释放引用并不能完全释放，需要单独循环释放。

  List<PdfReader> readerList = new List<PdfReader>();

    foreach (var rd in readerList)
             {
               rd.Dispose();
             }