powershellwin32gui

How do I use SetWindowText with Unicode in Win32 using PowerShell?

I'm trying to use PowerShell to change a Window title to display emojis.

I can change the Window title of a process (that has a window) using...

Add-Type -TypeDefinition @"
using System;
using System.Runtime.InteropServices;

public static class Win32 {
  [DllImport("User32.dll", EntryPoint="SetWindowText")]
  public static extern int SetWindowText(IntPtr hWnd, string strTitle);
}
"@

$MyNotepadProcess = start-process notepad -PassThru


[Win32]::SetWindowText($MyNotepadProcess.MainWindowHandle, 'My Title')

enter image description here

But using SetWindowText with emoji-codes just garbles the emoji characters in the output...

Using SetWindowTextW garbles the output for anything I pass to the function...

Add-Type -TypeDefinition @"
using System;
using System.Runtime.InteropServices;

public static class Win32 {
  [DllImport("User32.dll", EntryPoint="SetWindowTextW")]
  public static extern int SetWindowTextW(IntPtr hWnd, string strTitle);
}
"@

$MyNotepadProcess = start-process notepad -PassThru


[Win32]::SetWindowTextW($MyNotepadProcess.MainWindowHandle, 'My Title')

enter image description here

One issue I think I have, is that SetWindowTextW only accept wide string, but I don't know how to provide that as input.
And then I need to add the emojis using the Unicode numbers as in `u{1F600} (that's a :) too you).

(See Get Started with Win32 and C++ - Working with Strings)

Solution

  • The simplest way to ensure that the Unicode version of a WinAPI function is called properly is to:

    // Note the use of "CharSet=CharSet.Unicode" and 
// the function name *without suffix*
[DllImport("User32.dll", CharSet=CharSet.Unicode)]
public static extern int SetWindowText(IntPtr hWnd, string strTitle);

    This ensures that SetWindowTextW, i.e. the Unicode implementation of the function is called, and that .NET marshals the .NET string essentially as-is as as a native LPCWSTR string, i.e. as a null-terminated array of Unicode code units.