C# Definition:

[Flags()]
public enum DisplayDeviceStateFlags : int
{
    /// <summary>The device is part of the desktop.</summary>
    AttachedToDesktop = 0x1,
    MultiDriver = 0x2,
    /// <summary>The device is part of the desktop.</summary>
    PrimaryDevice = 0x4,
    /// <summary>Represents a pseudo device used to mirror application drawing for remoting or other purposes.</summary>
    MirroringDriver = 0x8,
    /// <summary>The device is VGA compatible.</summary>
    VGACompatible = 0x10,
    /// <summary>The device is removable; it cannot be the primary display.</summary>
    Removable = 0x20,
    /// <summary>The device has more display modes than its output devices support.</summary>
    ModesPruned = 0x8000000,
    Remote = 0x4000000,
    Disconnect = 0x2000000
}

VB.NET Definition:

<Flags()> _
Enum DisplayDeviceStateFlags As Integer
    ''' <summary>The device is part of the desktop.</summary>
    AttachedToDesktop = &H1
    MultiDriver = &H2
    ''' <summary>The device is part of the desktop.</summary>
    PrimaryDevice = &H4
    ''' <summary>Represents a pseudo device used to mirror application drawing for remoting or other purposes.</summary>
    MirroringDriver = &H8
    ''' <summary>The device is VGA compatible.</summary>
    VGACompatible = &H10
    ''' <summary>The device is removable; it cannot be the primary display.</summary>
    Removable = &H20
    ''' <summary>The device has more display modes than its output devices support.</summary>
    ModesPruned = &H8000000
    Remote = &H4000000
    Disconnect = &H2000000
End Enum

Notes:

See also DISPLAY_DEVICE