Trying to programmatically hold a key down - vb.net

Question

I'm trying to write an app to perform some basic process automation by sending keyboard events (i.e. simulating single key presses as well as holding keys down) to a window in focus (any window, such as Notepad). I can get single key presses to work just fine, but I can't get it to hold a key down. Even if I do a key down event, followed by a lengthy delay, followed by a key up... all I get is a single keypress.
I've read so many tutorials, and many of them multiple times over to ensure I haven't missed something. Every single time however, all I get is a single key press, it fails to hold the key down.
The following is a code sample I found from:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/bad5b1f3-cf59-4a2b-889b-257ee590bf99/vb-advanced-key-bot?forum=vbgeneral
What I'm expecting to have happen is that it would send a keyboard event that tells the system to hold down a key (e.g. aaaaaaaaaaaaaaaaaaaa), but all I get is a single character. I've tried spamming the system with repeat keypresses, but the receiving app sees the different keyboard code for keydowns and keyups, as opposed to a key in a held status, and thus is not responding as though the key were actually held key down.
What am I doing wrong? Did they maybe change this dll?
A huge thanks to anyone who can help me get this working.
Public Class Form1
Private Declare Sub keybd_event Lib "user32.dll" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Integer, ByVal dwExtraInfo As Integer)
Private Declare Function MapVirtualKey Lib "user32" Alias "MapVirtualKeyA" (ByVal wCode As Integer, ByVal wMapType As Integer) As Integer
' flag to indicate completion
Dim finished As Boolean = True
' how long to 'press' the Space key
Dim delay As Integer = 3
' how many times to repeat Q and Space
Dim Repeats As Integer
' User closes application during processing
Dim UserInterupt As Boolean = False
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
KeyPreview = True
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
If Not finished Then
TextBox1.AppendText("USER closing" & vbCrLf)
UserInterupt = True
e.Cancel = True
End If
End Sub
Private Sub Form1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles Me.KeyPress
Select Case e.KeyChar
Case "z", "Z"
e.Handled = True
Repeats = 12
finished = False
Do While Not finished
TextBox1.AppendText("Pressing SPACE" & vbCrLf)
HoldKeyDown(Keys.Space, delay)
Loop
Case "x", "X"
e.Handled = True
TextBox1.AppendText("USER stopping" & vbCrLf)
finished = True
End Select
End Sub
Private Sub HoldKeyDown(ByVal k As Keys, ByVal Hold As Integer)
Dim HoldFor As DateTime = DateTime.Now().AddSeconds(Hold)
keybd_event(k, MapVirtualKey(k, 0), 0, 0)
While HoldFor.Subtract(DateTime.Now()).TotalSeconds > 0
Application.DoEvents()
End While
keybd_event(k, MapVirtualKey(k, 0), 2, 0)
TextBox1.AppendText("SPACE released" & vbCrLf)
Repeats -= 1
If Repeats = 0 Then
finished = True
TextBox1.AppendText("REPEATS completed" & vbCrLf)
End If
If UserInterupt Then End
End Sub
End Class

Answer 1

Answering my own question after going right down the rabbit hole on this one.
Basically put, the only way to do this is with SendKeys. The other methods are all deprecated and so will not work in this way anymore.
However this isn't a dead-end for you. If you want to use SendKeys to "hold down" a key, then spam the key at 10ms intervals and this should trigger the receiving app to think the key is held down.