Read Method (PgSqlBlob)

In This Topic

Reads a sequence of bytes from the current PgSqlBlob stream and advances the position within the stream by the number of bytes read.

Syntax

Visual Basic
C#

'Declaration
 
Public Overrides Function Read( _
   ByVal buffer() As Byte, _
   ByVal offset As Integer, _
   ByVal count As Integer _
) As Integer

public override int Read( 
   byte[] buffer,
   int offset,
   int count
)

Parameters

buffer: The byte array buffer to be populated.
offset: The zero-based byte offset in the buffer.
count: The amount of bytes to read.

Return Value

The total number of bytes read into the buffer.

Remarks

The Read method reads a maximum of bytes from the current stream and stores them in buffer beginning at position. The current position within the stream is advanced by the number of bytes read. The Read method returns 0 if the position is at the end of the stream.

Example

In the example below a PgSqlBlob is created with 10 bytes in it. Then Position is changed using Seek method. An attempt to read 10 bytes is made afterwards, however, only 5 bytes remain till the end of the stream, so TargetArray is populated with 5 bytes only.

csharp

public void ReadFromMyBlob()
{
  byte[] myByteArray = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
  byte[] TargetArray = new Byte[15];
  PgSqlBlob myBlob = new PgSqlBlob(myByteArray);
  myBlob.Seek(5, SeekOrigin.Begin);
  Console.WriteLine(myBlob.Read(TargetArray, 0, 10) + " bytes are read");
}

Visual Basic

Public Sub ReadFromMyBlob()
  Dim myByteArray() As Byte = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  Dim TargetArray(15) As Byte
  Dim myBlob As PgSqlBlob = New PgSqlBlob(myByteArray)
  myBlob.Seek(5, SeekOrigin.Begin)
  Console.WriteLine(String.Concat(myBlob.Read(TargetArray, 0, 10), " bytes are read"))
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

PgSqlBlob Class
PgSqlBlob Members
Seek Method
Write Method

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