GetPgSqlBlob(Int32) Method

In This Topic

Gets the value of the specified column as a PgSqlBlob object.

Syntax

Visual Basic
C#

'Declaration
 
Public Overloads Function GetPgSqlBlob( _
   ByVal i As Integer _
) As PgSqlBlob

public PgSqlBlob GetPgSqlBlob( 
   int i
)

Parameters

i: The zero-based column ordinal.

Return Value

The value of the specified column as a PgSqlBlob object.

Example

This example shows how to download a BLOB field from a table using GetPgSqlBlob method.

csharp

public void DownloadBlob(PgSqlConnection pgConnection)
{
  PgSqlCommand pgCommand = new PgSqlCommand("SELECT * FROM Test.Pictures", pgConnection);
  pgConnection.Open();
  PgSqlDataReader pgReader = pgCommand.ExecuteReader(System.Data.CommandBehavior.Default);
  try
  {
    while (pgReader.Read())
    {
      PgSqlBlob myBlob = pgReader.GetPgSqlBlob(pgReader.GetOrdinal("Picture"));
      if(!myBlob.IsNull)
      {
        string FN = pgReader.GetString(pgReader.GetOrdinal("PicName"));
        FileStream fs = new FileStream("D:\\Tmp\\"+FN+".bmp", FileMode.Create);
        BinaryWriter w = new BinaryWriter(fs);
        w.Write(myBlob.Value);
        w.Close();
        fs.Close();
        Console.WriteLine(FN+" downloaded.");
      }
    }
  }
  finally
  {
    pgReader.Close();
    pgConnection.Close();
  }
}

Visual Basic

Public Sub DownloadBlob(ByVal pgConnection As PgSqlConnection)
  Dim pgCommand As New PgSqlCommand("SELECT * FROM Test.Pictures", pgConnection)
  pgConnection.Open()
  Dim pgReader As PgSqlDataReader = pgCommand.ExecuteReader(System.Data.CommandBehavior.Default)
  Try
    While pgReader.Read()
      Dim myBlob As PgSqlBlob = pgReader.GetPgSqlBlob(pgReader.GetOrdinal("Picture"))
      If Not myBlob.IsNull Then
        Dim FN As String = pgReader.GetString(pgReader.GetOrdinal("PicName"))
        Dim fs As FileStream = New FileStream("D:\Tmp\" + FN + ".bmp", FileMode.Create)
        Dim w As BinaryWriter = New BinaryWriter(fs)
        w.Write(myBlob.Value)
        w.Close()
        fs.Close()
        Console.WriteLine(String.Concat(FN, " downloaded."))
      End If
    End While
  Finally
    pgReader.Close()
    pgConnection.Close()
  End Try
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

PgSqlDataReader Class
PgSqlDataReader Members
Overload List
PgSqlBlob Class

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