Seek

Overrides Stream

This instance method sets the position on the current LOB stream.

Declaration

// C#
public override Int64 Seek(Int64 offset, SeekOrigin origin);

Parameters

offset

A byte offset relative to origin.
origin

A value of type System.IO.SeekOrigin indicating the reference point used to obtain the new position.

Return Value

Returns an Int64 that indicates the position.

Exceptions

ObjectDisposedException - The object is already disposed.

InvalidOperationException - The OracleConnection is not open or has been closed during the lifetime of the object.

Remarks

If offset is negative, the new position precedes the position specified by origin by the number of bytes specified by offset.

If offset is zero, the new position is the position specified by origin.

If offset is positive, the new position follows the position specified by origin by the number of bytes specified by offset.

SeekOrigin.Begin specifies the beginning of a stream.

SeekOrigin.Current specifies the current position within a stream.

SeekOrigin.End specifies the end of a stream.

Example

// Database Setup, if you have not done so yet.
/* Log on as DBA (SYS or SYSTEM) that has CREATE ANY DIRECTORY privilege.
 
CREATE OR REPLACE DIRECTORY MYDIR AS 'C:\TEMP';
 
*/
 
// C#
 
using System;
using System.IO;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;
 
class SeekSample
{
  static void Main()
  {
    // Create MYDIR directory object as indicated previously and create a file
    // MyFile.txt with the text ABCDABC under C:\TEMP directory.
    // Note that the byte representation of the ABCDABC is 65666768656667
 
    string constr = "User Id=scott;Password=tiger;Data Source=oracle";
    OracleConnection con = new OracleConnection(constr);
    con.Open();
 
    OracleBFile bFile = new OracleBFile(con, "MYDIR", "MyFile.txt");
 
    // Open the OracleBFile
    bFile.OpenFile();
    
    // Set the Position to 2 with respect to SeekOrigin.Begin
    long newPosition = bFile.Seek(2, SeekOrigin.Begin);
 
    // Prints "newPosition     = 2"
    Console.WriteLine("newPosition     = " + newPosition);    
 
    // Prints "bFile.Position  = 2"
    Console.WriteLine("bFile.Position  = " + bFile.Position);    
 
    // Read 2 bytes into readBuffer, starting at buffer offset 1
    byte[] readBuffer = new byte[4];    
    int bytesRead = bFile.Read(readBuffer, 1, 2);
    
    // Prints "bytesRead       = 2"
    Console.WriteLine("bytesRead       = " + bytesRead);    
 
    // Prints "readBuffer      = 067680"
    Console.Write("readBuffer      = ");
    for(int index = 0; index <  readBuffer.Length; index++)
    {
      Console.Write(readBuffer[index]);
    }
    Console.WriteLine();
    
    // Close the OracleBFile
    bFile.CloseFile();
 
    bFile.Close();
    bFile.Dispose();
 
    con.Close();
    con.Dispose();
  }
}