C# Signature:

[DllImport("user32.dll")]
static extern bool GetMenuItemInfo(IntPtr hMenu, uint uItem, bool fByPosition, ref MENUITEMINFO lpmii);

User-Defined Types:

MENUITEMINFO

Notes:

[StructLayout(LayoutKind.Sequential)]
public struct MENUITEMINFO
{
    public uint cbSize;
    public uint fMask;
    public uint fType;
    public uint fState;
    public int wID;
    public int hSubMenu;
    public int hbmpChecked;
    public int hbmpUnchecked;
    public int dwItemData;
    public string dwTypeData;
    public uint cch;
    public int hbmpItem;
}

// Values for the fMask parameter
//From winuser.h
const UInt32 MIM_MAXHEIGHT    =       0x00000001;
const UInt32 MIM_BACKGROUND   =       0x00000002;
const UInt32 MIM_HELPID       =       0x00000004;
const UInt32 MIM_MENUDATA     =       0x00000008;
const UInt32 MIM_STYLE    =       0x00000010;
const UInt32 MIM_APPLYTOSUBMENUS =    0x80000000;

Tips & Tricks:

Please add some!

Sample Code:

MENUITEMINFO mif = new MENUITEMINFO();
mif.cbSize = (uint)Marshal.SizeOf(typeof(MENUITEMINFO));
mif.fMask = 0x10;
mif.fType = 0;
mif.dwTypeData = null;
bool a = GetMenuItemInfo(hMenu, 0, true, ref mif);

Alternative Managed API:

Do you know one? Please contribute it!