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

Reference

MySqlDataReader Class
MySqlDataReader Members
Overload List
MySqlBlob Class

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