文件读取保存类

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CommHelper
{
 public class FilesAccess
 {
  public FilesAccess()
  { } 
 
  #region
  /// <summary>
  /// 把文件内容写入到物理位置
  /// </summary>
  /// <param name="as_filename"></param>
  /// <param name="a_FileData"></param>
  /// <returns></returns>
  public static string WriteFile(string as_filename, byte[] a_FileData)
        {
            string sRet = "";
   if (as_filename == "")
   {
    sRet = "请指定路径和文件名";
    return sRet;
   }
            try
            {
                System.IO.FileStream objFile = new System.IO.FileStream(as_filename,
                    System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite);
                System.IO.BinaryWriter objSW = new BinaryWriter(objFile, System.Text.Encoding.Unicode);
                objSW.BaseStream.Write(a_FileData, 0, a_FileData.Length);
                objSW.Close();
                objSW = null;
                objFile.Close();
                objFile = null;
            }
            catch (Exception ex)
            {
                sRet = ex.Message;
            }
            return sRet;
        }
  /// <summary>
  /// 把文件内容写入到物理位置
  /// </summary>
  /// <param name="as_filename"></param>
  /// <param name="as_FileData"></param>
  /// <returns></returns>
  public static string WriteFile(string as_filename,string as_FileData)
  {
   string sRet="";
   if (as_filename == "")
   {
    sRet = "请指定路径和文件名";
    return sRet;
   }
   try
   {
    System.IO.FileStream objFile=new System.IO.FileStream(as_filename,
     System.IO.FileMode.OpenOrCreate ,System.IO.FileAccess.ReadWrite ,System.IO.FileShare.ReadWrite );
    System.IO.BinaryWriter  objSW=new BinaryWriter(objFile,System.Text.Encoding.Unicode);
    byte[] tmpData=System.Text.Encoding.Unicode.GetBytes(as_FileData);
    objSW.BaseStream.Write(tmpData,0,tmpData.Length);
    objSW.Close();
    objSW=null;
    objFile.Close();
    objFile=null;
    sRet="";
   }
   catch(Exception exp)
   {
    sRet=exp.Message;
   }
   return sRet;
  }
  /// <summary>
  /// 读取物理位置文件内容
  /// </summary>
  /// <param name="as_filename"></param>
  /// <returns></returns>
  public static byte[] ReadFile(string as_filename)
  {
   byte[] tmpData = null;
   if (as_filename == "")
   {
    return tmpData;
   }
   byte[] tmpAddData = new byte[1024 * 1024];
   int intNum = 0;
   int intReadLen = 0;
   long lngLen = 0;
   System.IO.FileStream objFile = new System.IO.FileStream(as_filename,
    System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
   System.IO.BinaryReader objSR = new System.IO.BinaryReader(objFile, System.Text.Encoding.Unicode);
   tmpData = new byte[objSR.BaseStream.Length];
   while (true)
   {
    intReadLen = objSR.Read(tmpAddData, 0, tmpAddData.Length);
    Array.Copy(tmpAddData, 0, tmpData, lngLen, intReadLen);
    lngLen = lngLen + intReadLen;
    intNum = intNum + 1;
    if (intReadLen <= 0)
    {
     break;
    }
   }
   objSR.Close();
   objSR = null;
   objFile.Close();
   objFile = null;
   return tmpData;
  }
  /// <summary>
  /// 读取物理位置文件的内容
  /// </summary>
  /// <param name="as_filename"></param>
  /// <param name="as_FileData"></param>
  /// <returns></returns>
  public static string ReadFile(string as_filename, out byte[] as_FileData)
  {
   string sRet = "";
   as_FileData = null;
   byte[] tmpData = null;
   if (as_filename == "")
   {
    sRet = "请指定路径和文件名";
    return sRet;
   }
   try
   {
    byte[] tmpAddData = new byte[1024 * 1024];
    int intNum = 0;
    int intReadLen = 0;
    long lngLen = 0;
    System.IO.FileStream objFile = new System.IO.FileStream(as_filename,
     System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
    System.IO.BinaryReader objSR = new System.IO.BinaryReader(objFile, System.Text.Encoding.Unicode);
    tmpData = new byte[objSR.BaseStream.Length];
    while (true)
    {
     intReadLen = objSR.Read(tmpAddData, 0, tmpAddData.Length);
     Array.Copy(tmpAddData, 0, tmpData, lngLen, intReadLen);
     lngLen = lngLen + intReadLen;
     intNum = intNum + 1;
     if (intReadLen <= 0)
     {
      break;
     }
    }
    objSR.Close();
    objSR = null;
    objFile.Close();
    objFile = null;
    as_FileData = tmpData;
   }
   catch (Exception ex)
   {
    sRet = ex.Message.ToString();
    as_FileData = null;
   }
   return sRet;
  }

  /// <summary>
  /// 从物理位置读取文件内容
  /// </summary>
  /// <param name="as_filename"></param>
  /// <param name="asFileData"></param>
  /// <returns></returns>
  public static string ReadFile(string as_filename, out string as_FileData)
  {
   string sRet = "";
   as_FileData = "";
   try
   {
    if (as_filename == "")
    {
     sRet = "请指定路径和文件名";
     return sRet;
    }
    byte[] tmpData;
    byte[] tmpAddData = new byte[1024 * 1024];
    int intNum = 0;
    int intReadLen = 0;
    long lngLen = 0;
    System.IO.FileStream objFile = new System.IO.FileStream(as_filename,
     System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
    System.IO.BinaryReader objSR = new System.IO.BinaryReader(objFile, System.Text.Encoding.Unicode);
    tmpData = new byte[objSR.BaseStream.Length];
    while (true)
    {
     intReadLen = objSR.Read(tmpAddData, 0, tmpAddData.Length);
     Array.Copy(tmpAddData, 0, tmpData, lngLen, intReadLen);
     lngLen = lngLen + intReadLen;
     intNum = intNum + 1;
     if (intReadLen <= 0)
     {
      break;
     }
    }
    as_FileData = System.Text.Encoding.Unicode.GetString(tmpData);
    objSR.Close();
    objSR = null;
    objFile.Close();
    objFile = null;
    sRet = "";
   }
   catch (Exception eRead)
   {
    sRet = eRead.Message.ToString();
    as_FileData = "";
   }
   return sRet;
  }
  /// <summary>
  /// 把文件内容写入到物理位置
  /// </summary>
  /// <param name="as_filename"></param>
  /// <param name="as_FileData"></param>
  /// <returns></returns>
  public static string WriteFile_UTF8(string as_filename,string as_FileData)
  {
   string sRet="";
   try
   {
    if(as_filename=="")
    {
     sRet="请指定路径和文件名";
     return sRet;
    }
    System.IO.FileStream objFile=new System.IO.FileStream(as_filename,
     System.IO.FileMode.OpenOrCreate ,System.IO.FileAccess.ReadWrite ,System.IO.FileShare.ReadWrite );
    System.IO.BinaryWriter  objSW=new BinaryWriter(objFile,System.Text.Encoding.UTF8);
    byte[] tmpData=System.Text.Encoding.UTF8.GetBytes(as_FileData);
    objSW.BaseStream.Write(tmpData,0,tmpData.Length);
    objSW.Close();
    objSW=null;
    objFile.Close();
    objFile=null;
    sRet="";
   }
   catch(Exception exp)
   {
    sRet=exp.Message;
   }
   return sRet;
  }

     #endregion
 }
}