Null Field (MySqlBlob)

In This Topic

Represents a null MySqlBlob object.

Syntax

Visual Basic
C#

'Declaration
 
Public Shadows Shared ReadOnly Null As MySqlBlob

public new static readonly MySqlBlob Null

Example

In this sample a Null value is assigned to a MySqlBlob instance, then some properties are checked. If unchanged, this code produces the following output:

It is empty.

It is Null.

csharp

public void MySqlBlobNullTest()
{
  MySqlBlob myBlob = new MySqlBlob();
  myBlob = MySqlBlob.Null;
  if (myBlob.CanRead)
  {
    Console.WriteLine("It can read.");
  }
  if (myBlob.CanWrite)
  {
    Console.WriteLine("It can write.");
  }
  if (myBlob.CanSeek)
  {
    Console.WriteLine("It can seek.");
  }
  if (myBlob.IsEmpty)
  {
    Console.WriteLine("It is empty.");
  }
  if (myBlob.IsNull)
  {
    Console.WriteLine("It is Null.");
  }
}

Visual Basic

Public Sub MySqlBlobNullTest()
  Dim myBlob As MySqlBlob = New MySqlBlob
  myBlob = MySqlBlob.Null
  If myBlob.CanRead Then
    Console.WriteLine("It can read.")
  End If
  If myBlob.CanWrite Then
    Console.WriteLine("It can write.")
  End If
  If (myBlob.CanSeek) Then
    Console.WriteLine("It can seek.")
  End If
  If myBlob.IsEmpty Then
    Console.WriteLine("It is empty.")
  End If
  If myBlob.IsNull Then
    Console.WriteLine("It is Null.")
  End If
End Sub

Remarks

Use field Null to assign to a MySqlBlob in order to represent a Null value. In this case a BLOB inserted in a field of a table will be Null rather than zero-length byte array.

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

MySqlBlob Class
MySqlBlob Members

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