GetPgSqlBlob(String) 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 name As String _
) As PgSqlBlob

public PgSqlBlob GetPgSqlBlob( 
   string name
)

Parameters

name: The name of the column to get value of.

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

Reference

PgSqlDataReader Class
PgSqlDataReader Members
Overload List
PgSqlBlob Class

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