转自https://blog.csdn.net/liubowei_0312/article/details/53378146

适合将文件写入数据库，远程访问的时候还原
1.首先把文件转成十六进制文件流
public void FileToStream()
{
try
{
IPdfClassBll pdfClassBll = DataFactory.GetPdfClass();
FileStream fs = new FileStream(@"文件路径/***.PDF", FileMode.Open);
BinaryReader br = new BinaryReader(fs);
Byte[] byData = br.ReadBytes((int)fs.Length);
StringBuilder strResult = new StringBuilder(byData.Length * 8);
string binary = byteToHexStr(byData);
PdfInfo pdfinfo = new PdfInfo();
pdfinfo.PRTNUM = "PH001";//创建的新文件名
pdfinfo.PDFREPORT = binary;
pdfClassBll.Add(pdfinfo);
fs.Close();
br.Close();
}
catch (Exception ex)
{
MessageBox.Show("文件写入失败~！");
}
}

/// <summary>
/// 字节数组转16进制字符串
/// </summary>
/// <param name="bytes"></param>
/// <returns></returns>
public static string byteToHexStr(byte[] bytes)
{
string returnStr = "";
if (bytes != null)
{
for (int i = 0; i < bytes.Length; i++)
{
returnStr += bytes[i].ToString("X2");
}
}
return returnStr;
}

2.读取数据库中的 PDF流 信息，并写入文件
=======================

public void StreamToFile(string prtnum)
{
try
{
//写入位置
SampleConfig config = MonitorConfigManager.GetInstance().GetSampleConfig();
string reportPath = config.ReportPath;
reportPath = reportPath + "\\" + oSampleInfo.PRTNUM + ".pdf";
IPdfClassBll pdfClassBll = DataFactory.GetPdfClass();
PdfInfo pdfInfo = pdfClassBll.GetPdfReportByPRTNUM(prtnum);
string strPdf = pdfInfo.PDFREPORT;
byte[] bytes = strToToHexByte(strPdf);
FileStream fileStream = new FileStream(reportPath, FileMode.OpenOrCreate, FileAccess.Write);
fileStream.Write(bytes, 0, bytes.Length);
BinaryWriter binaryWriter = new BinaryWriter(fileStream);
binaryWriter.Write(bytes);
binaryWriter.Close();
fileStream.Close();
}
catch (Exception ex)
{

}
}
/// <summary>
/// 16进制字符串转为文字
/// </summary>
/// <param name="hexString"></param>
/// <returns></returns>
private static byte[] strToToHexByte(string hexString)
{
hexString = hexString.Replace(" ", "");
if ((hexString.Length % 2) != 0)
hexString += " ";
byte[] returnBytes = new byte[hexString.Length / 2];
for (int i = 0; i < returnBytes.Length; i++)
returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);

return returnBytes;
}