using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Custom.UserControls
{
  /// <summary>
  /// Most controls, even when on an inactive window, respond
  /// to clicks by activating and then processing the click.
  ///
  /// The ToolStrip and MenuStrip don't activate first, so the click
  /// event won't even be caught.
  /// </summary>
  public partial class ClickThroughToolStrip : ToolStrip
  {
    private bool clickThroughEnabled;

    /// <summary>
    /// Enable click through, or not.
    /// </summary>
    public bool ClickThroughEnabled
    {
      get { return clickThroughEnabled; }
      set { clickThroughEnabled = value; }
    }

    public ClickThroughToolStrip() : base()
    {
      /// Enable click-through behavior by default
      clickThroughEnabled = true;
    }


    protected override void WndProc(ref Message m)
    {
      /// Allow the ToolStrip to process as usual
      base.WndProc(ref m);

      /// If click-through is enabled we may have a need to
      /// activate this window
      if (clickThroughEnabled)
      {
        /// Use Winspector to spy on the ToolStrip.  When the
        /// window isn't selected and you click a ToolStrip button, the
        /// WM_MOUSEACTIVATE message is fired with an activate code of 
        /// MA_ACTIVATEANDEAT (we'd prefer just MA_ACTIVATE)
        if (m.Msg == Messages.WM_MOUSEACTIVATE && m.Result == Messages.MA_ACTIVATEANDEAT)
          m.Result = Messages.MA_ACTIVATE;
      }
    }

  }

  /// <summary>
  /// The Windows messages this control needs
  /// </summary>
  internal sealed class Messages
  {
    public static int WM_MOUSEACTIVATE = 0x21;
    public static IntPtr MA_ACTIVATEANDEAT = (IntPtr)2;
    public static IntPtr MA_ACTIVATE = (IntPtr)1;
  }

}