Bring Window To Foreground When MainWindowHandle Is 0

Question

The following code brings the window to the foreground, if the MainWindowHandle is not 0.

How can I bring a window to the front that has MainWindowHandle = 0?

This is for the Microsoft Excel - Compatibility Checker window that shows a GUI but does not have an icon in the task bar and has MainWindowHandle = 0.

I have no other instances of Excel running.

Add-Type @"
  using System;
  using System.Runtime.InteropServices;
  public class Tricks {
     [DllImport("user32.dll")]
     [return: MarshalAs(UnmanagedType.Bool)]
     public static extern bool SetForegroundWindow(IntPtr hWnd);
  }
"@

$excel = (Get-Process | Where-Object { $_.ProcessName -eq 'EXCEL' }).MainWindowHandle
[void] [Tricks]::SetForegroundWindow($excel)

In Windows Task Manager, I can right click on 'Microsoft Excel - Compatibility Checker' and click on "Bring To Front" and that works. How can I mimic this functionality in Powershell?

Answer 1

Thanks to IInspectable for pointing me in the right direction.

This code gets the real MainWindowHandle value:

$TypeDef2 = @"

using System;
using System.Text;
using System.Collections.Generic;
using System.Runtime.InteropServices;

namespace Api
{

public class WinStruct
{
   public string WinTitle {get; set; }
   public int MainWindowHandle { get; set; }
}

public class ApiDef
{
   private delegate bool CallBackPtr(int hwnd, int lParam);
   private static CallBackPtr callBackPtr = Callback;
   private static List<WinStruct> _WinStructList = new List<WinStruct>();

   [DllImport("User32.dll")]
   [return: MarshalAs(UnmanagedType.Bool)]
   private static extern bool EnumWindows(CallBackPtr lpEnumFunc, IntPtr lParam);

   [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
   static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

   private static bool Callback(int hWnd, int lparam)
   {
       StringBuilder sb = new StringBuilder(256);
       int res = GetWindowText((IntPtr)hWnd, sb, 256);
      _WinStructList.Add(new WinStruct { MainWindowHandle = hWnd, WinTitle = sb.ToString() });
       return true;
   }  

   public static List<WinStruct> GetWindows()
   {
      _WinStructList = new List<WinStruct>();
      EnumWindows(callBackPtr, IntPtr.Zero);
      return _WinStructList;
   }

}
}
"@

Add-Type -TypeDefinition $TypeDef2 -Language CSharpVersion3

$excelInstance = [Api.Apidef]::GetWindows() | Where-Object { $_.WinTitle.ToUpper() -eq "Microsoft Excel - Compatibility Checker".ToUpper() }

So now using this correct value, I can call the SetForegroundWindow() function:

Add-Type @"
  using System;
  using System.Runtime.InteropServices;
  public class Tricks {
     [DllImport("user32.dll")]
     [return: MarshalAs(UnmanagedType.Bool)]
     public static extern bool SetForegroundWindow(IntPtr hWnd);
  }
"@
[void] [Tricks]::SetForegroundWindow($excelInstance.MainWindowHandle)

I wrote a detailed blog about this on my website .

I've put up a full example on GitHub of how to create an Excel file, edit it and run the above code in a different thread which you have to do because the Excel popup blocks the main thread.