Getting items from an MFC list control from .NET
[DllImport( "user32.dll", SetLastError = true )]
        public static extern uint GetDlgItemText( IntPtr hDlg, int nIDDlgItem, [Out] StringBuilder lpString, int nMaxCount );

[DllImport( "User32", SetLastError = true )]
        public static extern IntPtr GetDlgItem( IntPtr hwndParent, int ItemId );

private string GetSelectedItem()
{
    string item = null;

    IntPtr pStringBuffer = Marshal.AllocHGlobal(2048);
    IntPtr pItemBuffer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(LVITEM)));

    int selectedItemIndex = SendMessage(base.Handle, LVM_GETNEXTITEM, (IntPtr)(-1), (IntPtr)LVNI_SELECTED).ToInt32();
    if (selectedItemIndex > -1)
    {
        LVITEM lvi = new LVITEM();
        lvi.cchTextMax = 1024;
        lvi.pszText = pStringBuffer;
        Marshal.StructureToPtr(lvi, pItemBuffer, false);
        int numChars = SendMessage(base.Handle, LVM_GETITEMTEXT, (IntPtr)selectedItemIndex, pItemBuffer).ToInt32();
        if (numChars > 0)
        {
            item = Marshal.PtrToStringUni(lvi.pszText, numChars);
        }
    }

    Marshal.FreeHGlobal(pStringBuffer);
    Marshal.FreeHGlobal(pItemBuffer);

    return item;
}

struct LVITEM
{
    public int mask;
    public int iItem;
    public int iSubItem;
    public int state;
    public int stateMask;
    public IntPtr pszText;
    public int cchTextMax;
    public int iImage;
    public IntPtr lParam;
    public int iIndent;
    public int iGroupId;
    int cColumns; // tile view columns
    public IntPtr puColumns;
    public IntPtr piColFmt;
    public int iGroup;

}