<script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script><script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script> 這裡有關於用C#讀取資料庫中的Image資料的介紹，
誰知道該怎麼把Image物件寫入資料庫，？以及對資料庫中Image物件
進行檢索？
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從資料庫中獲取 BLOB 值

DataReader 的預設行為是在整個資料行可用時立即以行的形式載入傳入資料。但是，對於二進位制大物件 (BLOB) 則需要進行不同的處理，因為它們可能包含數十億位元組的資料，而單個行中無法包含如此多的資料。Command.ExecuteReader 方法具有一個過載，它將採用 CommandBehavior 引數來修改 DataReader 的預設行為。您可以將 CommandBehavior.SequentialAccess 傳遞到 ExecuteReader 方法來修改 DataReader 的預設行為，以便讓 DataReader 按照順序在接收到

資料時立即將其載入，而不是載入資料行。這是載入 BLOB 或其他大資料結構的理想方案。

在將 DataReader 設定為使用 SequentialAccess 時，務必要注意訪問所返回欄位的順序。DataReader 的預設行為是在整個行可用時立即載入該行，這使您能夠在讀取下一行之前按任何順序訪問所返回的欄位。但是，當使用 SequentialAccess 時，必須按順序訪問由 DataReader 返回的不同欄位。例如，如果查詢返回三個列，其中第三列是 BLOB，則必須在訪問第三個欄位中的 BLOB 資料之前返回第一個和第二個欄位的值。如果在訪問第一個或第二個欄位之前訪問第三個欄位，則第一個和第二個欄位值將不再可用。這是因為 SequentialAccess 已修改 DataReader，使其按順序返回

資料，當 DataReader 已經讀取超過特定資料時，該資料將不可用。

當訪問 BLOB 欄位中的資料時，請使用 DataReader 的 GetBytes 型別化訪問器，該訪問器將使用二進位制資料填充 byte 陣列。您可以指定要返回的特定資料緩衝區大小以及從返回的資料中讀取的第一個位元組的起始位置。GetBytes 將返回 long 值，它表示所返回的位元組數。如果向 GetBytes 傳遞空的 byte 陣列，所返回的長值將是 BLOB 中位元組的總數。您可以選擇將位元組陣列中的某索引指定為所讀取資料的起始位置。

以下示例從 Microsoft SQL Server 中的 pubs 示例資料庫中返回發行者 ID 和徽標。發行者 ID (pub_id) 是字元欄位，而徽標則是圖形，即 BLOB。請注意，由於必須按順序訪問欄位，所以將在訪問徽標之前訪問當前資料行的發行者 ID。

[Visual Basic]
Dim pubsConn As SqlConnection = New SqlConnection("Data Source=localhost;Integrated Security=SSPI;Initial Catalog=pubs;")
Dim logoCMD As SqlCommand = New SqlCommand("SELECT pub_id, logo FROM pub_info", pubsConn)

Dim fs As FileStream                 ' Writes the BLOB to a file (*.bmp).
Dim bw As BinaryWriter               ' Streams the binary data to the FileStream object.

Dim bufferSize As Integer = 100      ' The size of the BLOB buffer.
Dim outbyte(bufferSize - 1) As Byte  ' The BLOB byte() buffer to be filled by GetBytes.
Dim retval As Long                   ' The bytes returned from GetBytes.
Dim startIndex As Long = 0           ' The starting position in the BLOB output.

Dim pub_id As String = ""            ' The publisher id to use in the file name.

' Open the connection and read data into the DataReader.
pubsConn.Open()
Dim myReader As SqlDataReader = logoCMD.ExecuteReader(CommandBehavior.SequentialAccess)

Do While myReader.Read()
  ' Get the publisher id, which must occur before getting the logo.
  pub_id = myReader.GetString(0)

  ' Create a file to hold the output.
  fs = New FileStream("logo" & pub_id & ".bmp", FileMode.OpenOrCreate, FileAccess.Write)
  bw = New BinaryWriter(fs)

  ' Reset the starting byte for a new BLOB.
  startIndex = 0

  ' Read bytes into outbyte() and retain the number of bytes returned.
  retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize)

  ' Continue reading and writing while there are bytes beyond the size of the buffer.
  Do While retval = bufferSize
    bw.Write(outbyte)
    bw.Flush()

    ' Reposition the start index to the end of the last buffer and fill the buffer.
    startIndex = startIndex + bufferSize
    retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize)
  Loop

  ' Write the remaining buffer.
  bw.Write(outbyte)
  bw.Flush()

  ' Close the output file.
  bw.Close()
  fs.Close()
Loop

' Close the reader and the connection.
myReader.Close()
pubsConn.Close()
[C#]
SqlConnection pubsConn = new SqlConnection("Data Source=localhost;Integrated Security=SSPI;Initial Catalog=pubs;");
SqlCommand logoCMD = new SqlCommand("SELECT pub_id, logo FROM pub_info", pubsConn);

FileStream fs;                          // Writes the BLOB to a file (*.bmp).
BinaryWriter bw;                        // Streams the BLOB to the FileStream object.

int bufferSize = 100;                   // Size of the BLOB buffer.
byte[] outbyte = new byte[bufferSize];  // The BLOB byte[] buffer to be filled by GetBytes.
long retval;                            // The bytes returned from GetBytes.
long startIndex = 0;                    // The starting position in the BLOB output.

string pub_id = "";                     // The publisher id to use in the file name.

// Open the connection and read data into the DataReader.
pubsConn.Open();
SqlDataReader myReader = logoCMD.ExecuteReader(CommandBehavior.SequentialAccess);

while (myReader.Read())
{
  // Get the publisher id, which must occur before getting the logo.
  pub_id = myReader.GetString(0);  

  // Create a file to hold the output.
  fs = new FileStream("logo" + pub_id + ".bmp", FileMode.OpenOrCreate, FileAccess.Write);
  bw = new BinaryWriter(fs);

  // Reset the starting byte for the new BLOB.
  startIndex = 0;

  // Read the bytes into outbyte[] and retain the number of bytes returned.
  retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);

  // Continue reading and writing while there are bytes beyond the size of the buffer.
  while (retval == bufferSize)
  {
    bw.Write(outbyte);
    bw.Flush();

    // Reposition the start index to the end of the last buffer and fill the buffer.
    startIndex+= bufferSize;
    retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);
  }

  // Write the remaining buffer.
  bw.Write(outbyte);
  bw.Flush();

  // Close the output file.
  bw.Close();
  fs.Close();
}

// Close the reader and the connection.
myReader.Close();
pubsConn.Close();


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