#眉標=TxF、P/Invoke、AlphaFS
#副標=交易式的檔案處理(2)
#大標=結合檔案及資料庫的交易處理
#作者=文／圖 吳剛志


======<box>===========
程式1 

string connstr = 
  ConfigurationManager.ConnectionStrings["photoDB"].ConnectionString;
using (SqlConnection conn = new SqlConnection(connstr))
{
  conn.Open();
  SqlCommand cmd = conn.CreateCommand();
  cmd.CommandText = @"
  insert photos (Description, ImagePath) values 
  (@desc, @path); 
  select NULLIF(SCOPE_IDENTITY(), 0);";
  foreach (UploadPhotoData p in this.GetUploadPhotos())
  {
   string path = string.Format(
	"{0:N}.jpg", 
    Guid.NewGuid());
   p.FileUploadControl.SaveAs(
	this.Server.MapPath("~/App_Data/photos/" + path));
   this.Trace.Write(
    string.Format("檔案({0}) 上傳成功", path));
    cmd.Parameters.Clear();
    cmd.Parameters.AddWithValue(
    "desc", 
    p.TextBoxControl.Text);
    cmd.Parameters.AddWithValue("path", path);
    int resultPK = (int)(decimal)cmd.ExecuteScalar();
    this.Trace.Write(string.Format(
    "資料庫 [photos.PK: {0}] 更新成功", resultPK));
  }
}
==<end>==============





=====<box>===========
程式2

//用TransactionScope標示交易範圍
using (TransactionScope scope = new TransactionScope()) {
  //更新檔案
  //更新資料庫
  // throw new Exception("cancel transaction");
  //認可scope範圍內的交易
  scope.Complete();
}
==<end>==============






=====<box>===========
程式3

SafeFileHandle fh = CreateFileTransacted(
  this.Server.MapPath("~/App_Data/photos/" + path),
  0x40000000,
  0x00000000,
  IntPtr.Zero,
  0x00000001,
  0x00000080,
  IntPtr.Zero,
  kth,
  IntPtr.Zero,
  IntPtr.Zero);

Stream source = 
  p.FileUploadControl.PostedFile.InputStream;
Stream target = 
  new FileStream(fh, FileAccess.Write);

byte[] buffer = new byte[4096];
int count = 0;

while ((count = 
  source.Read(buffer, 0, buffer.Length)) > 0)
{
  target.Write(buffer, 0, count);
}

source.Close();
target.Close();
this.Trace.Write(string.Format(
  "檔案({0})上傳成功", 
  path));
==<end>==============





==<box>===========
程式4

IDtcTransaction dtc = 
  TransactionInterop.GetDtcTransaction(
	Transaction.Current);
IKernelTransaction ktm = (IKernelTransaction)dtc;
IntPtr kth;
ktm.GetHandle(out kth);
==<end>==============





==<box>===========
程式5 

using (TransactionScope scope = 
  new TransactionScope()) {
  try
  {
//準備交易物件Handle: kth
   IDtcTransaction dtc = 
	TransactionInterop.GetDtcTransaction(
	 Transaction.Current);
    IKernelTransaction ktm = 
	 (IKernelTransaction)dtc;
    IntPtr kth;
    ktm.GetHandle(out kth);

using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["photoDB"].ConnectionString))
  {
   conn.Open();
   SqlCommand cmd = conn.CreateCommand();
   cmd.CommandText = @"
insert photos (Description, ImagePath) 
values (@desc, @path); 
select NULLIF(SCOPE_IDENTITY(), 0);";

  foreach (UploadPhotoData p in 
   this.GetUploadPhotos())
    string path = string.Format(
     "{0:N}.jpg",
    Guid.NewGuid());

// 取得檔案的 Handle
  SafeFileHandle fh = 
   CreateFileTransacted(
    this.Server.MapPath(
     "~/App_Data/photos/" + path),
      0x40000000,
      0x00000000,
      IntPtr.Zero,
      0x00000001,
      0x00000080,
    IntPtr.Zero,
    kth,
    IntPtr.Zero,
    IntPtr.Zero);

  Stream source = p.FileUploadControl.PostedFile.InputStream;
  Stream target = new FileStream(fh, FileAccess.Write);

// 複製 Stream
  byte[] buffer = new byte[4096];
  int count = 0;
  while ((count = 
   source.Read(buffer, 0, buffer.Length)) > 0)
    {
     target.Write(buffer, 0, count);
    }
   source.Close();
   target.Close();
   this.Trace.Write(string.Format(
    "檔案 ({0}) 上傳成功", 
     path));

// 寫入資料庫
  cmd.Parameters.Clear();
  cmd.Parameters.AddWithValue(
    "desc", 
    p.TextBoxControl.Text);
  cmd.Parameters.AddWithValue(
    "path", 
    path);
  int resultPK = 
     (int)(decimal)cmd.ExecuteScalar();
  this.Trace.Write(string.Format(
    "資料庫 [photos.PK: {0}] 更新成功", 
    resultPK));
    }
  }

//throw new Exception("cancel transaction");
  scope.Complete();
   }
   catch (Exception ex)
   {
    this.Trace.Warn("Exception", ex.ToString());
    this.Trace.Warn("Transaction Rollback.");
     throw;
  }
}
==<end>==============




======<box>===========
程式6 
using (TransactionScope scope = 
  new TransactionScope())
{
  try
  {
//透過Ambient Transaction，取得KernelTransaction物件
  KernelTransaction ktm = 
    new KernelTransaction(Transaction.Current);
   using (SqlConnection conn = 
    new SqlConnection(ConfigurationManager.ConnectionStrings["photoDB"].ConnectionString))
    {
//開啟資料庫連線，及準備SqlCommand物件，略
    foreach (UploadPhotoData p in this.GetUploadPhotos())
    {
     string path = string.Format(
     "{0:N}.jpg",
     Guid.NewGuid());
     Stream source = p.FileUploadControl.PostedFile.InputStream;
//以支援交易的方式開啟檔案
     Stream target = File.Open(
      ktm,
      this.Server.MapPath("~/App_Data/photos/" + path),
      FileMode.Create,
      FileAccess.Write);
//複製Stream，略
      this.Trace.Write(string.Format(
      "檔案{0}上傳成功", path));
//寫入資料庫，略
     }
    }
  throw new Exception("cancel transaction");
  scope.Complete();
  }
   catch (Exception ex)
   {
    this.Trace.Warn("Exception", ex.ToString());
    this.Trace.Warn("Transaction Rollback.");
   throw;
   }
}
==<end>==============


本文的完整範例程式，可至www.runpc.com.tw，或是筆者部落格：columns.chicken-house.net/category/RUNPC.aspx上下載。