C# Signature:

  [StructLayout(LayoutKind.Sequential)]
  public struct APPBARDATA
  {
    public int cbSize; // initialize this field using: Marshal.SizeOf(typeof(APPBARDATA));
    public IntPtr hWnd;
    public uint uCallbackMessage;
    public uint uEdge;
    public RECT rc;
    public int lParam;
  }

VB Signature:

  <StructLayout(LayoutKind.Sequential)> Structure APPBARDATA
    Public cbSize As Integer
    Public hWnd As IntPtr
    Public uCallbackMessage As Integer
    Public uEdge As Integer
    Public rc As RECT
    Public lParam As IntPtr
  End Structure

User-Defined Types:

None.

Notes:

Initialy the C# signature in this article used a public static readonly int for cbSize so it could be initialized inline but the static field is then no longer where you expect it to be in memory so the call to SHAppBarMessage() fails. The field cannot be static.

Tips & Tricks:

If you want a single line way to get an APBARDATA with the cbSize field initialized then you can add a public static method as follows:

  [StructLayout(LayoutKind.Sequential)]
  public struct APPBARDATA
  {
    public int cbSize; // initialize this field using: Marshal.SizeOf(typeof(APPBARDATA));
    public IntPtr hWnd;
    public uint uCallbackMessage;
    public uint uEdge;
    public RECT rc;
    public int lParam;
    public static APPBARDATA NewAPPBARDATA()
    {
      APPBARDATA abd = new APPBARDATA();
      abd.cbSize = Marshal.SizeOf(typeof(APPBARDATA));
      return abd;
    }
  }

  ...
  APPBARDATA myBarData = APPBARDATA.NewAPPBARDATA();
  myBarData.hWnd = MyBar.Handle;
  ...

Sample Code:

Please add some!

Alternative Managed API:

Do you know one? Please contribute it!