C# Definition:

/// <summary>Value type for raw input devices.</summary>
[StructLayout(LayoutKind.Sequential)]
public struct RAWINPUTDEVICE
{
    /// <summary>Top level collection Usage page for the raw input device.</summary>
    public HIDUsagePage UsagePage;
    /// <summary>Top level collection Usage for the raw input device. </summary>
    public HIDUsage Usage;
    /// <summary>Mode flag that specifies how to interpret the information provided by UsagePage and Usage.</summary>
    public RawInputDeviceFlags Flags;
    /// <summary>Handle to the target device. If NULL, it follows the keyboard focus.</summary>
    public IntPtr WindowHandle;
}

VB.NET Definition:

''' <summary>Value type for raw input devices.</summary>
<StructLayout(LayoutKind.Sequential)> _
Public Structure RAWINPUTDEVICE
    ''' <summary>Top level collection Usage page for the raw input device.</summary>
    Public UsagePage As HIDUsagePage
    ''' <summary>Top level collection Usage for the raw input device. </summary>
    Public Usage As HIDUsage
    ''' <summary>Mode flag that specifies how to interpret the information provided by UsagePage and Usage.</summary>
    Public Flags As RawInputDeviceFlags
    ''' <summary>Handle to the target device. If NULL, it follows the keyboard focus.</summary>
    Public WindowHandle As IntPtr
End Structure

User-Defined Types:

HIDUsagePage, HIDUsage, RawInputDeviceFlags

Notes:

None.