GetMySqlBlob(Int32) Method

In This Topic

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

Syntax

Visual Basic
C#

'Declaration
 
Public Overloads Function GetMySqlBlob( _
   ByVal i As Integer _
) As MySqlBlob

public MySqlBlob GetMySqlBlob( 
   int i
)

Parameters

i: The zero-based column ordinal.

Return Value

The value of the specified column as a MySqlBlob object.

Example

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

csharp

public void DownloadBlob(MySqlConnection myConnection)
{
  MySqlCommand myCommand = new MySqlCommand("SELECT * FROM Test.Pictures", myConnection);
  myConnection.Open();
  MySqlDataReader myReader = myCommand.ExecuteReader(System.Data.CommandBehavior.Default);
  try
  {
    while (myReader.Read())
    {
      MySqlBlob myBlob = myReader.GetMySqlBlob(myReader.GetOrdinal("Picture"));
      if(!myBlob.IsNull)
      {
        string FN = myReader.GetString(myReader.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
  {
    myReader.Close();
    myConnection.Close();
  }
}

Visual Basic

Public Sub DownloadBlob(ByVal myConnection As MySqlConnection)
  Dim myCommand As New MySqlCommand("SELECT * FROM Test.Pictures", myConnection)
  myConnection.Open()
  Dim myReader As MySqlDataReader = myCommand.ExecuteReader(System.Data.CommandBehavior.Default)
  Try
    While myReader.Read()
      Dim myBlob As MySqlBlob = myReader.GetMySqlBlob(myReader.GetOrdinal("Picture"))
      If Not myBlob.IsNull Then
        Dim FN As String = myReader.GetString(myReader.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
    myReader.Close()
    myConnection.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

MySqlDataReader Class
MySqlDataReader Members
Overload List
MySqlBlob Class

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