Expression cannot be converted to long error - vb.net

Question

im getting the following error, and have no idea how to solve this:
BC30581: Adressoff Expression cannot be converted to Long because Long is not a delegate type.
Public Declare Function SetTimer Lib "user32" (
ByVal HWnd As Long,
ByVal nIDEvent As Long,
ByVal uElapse As Long,
ByVal lpTimerFunc As Long) As Long
Public Declare Function KillTimer Lib "user32" (
ByVal HWnd As Long,
ByVal nIDEvent As Long) As Long
Public TimerID As Long
Public TimerSeconds As Single
Sub StartTimer()
TimerSeconds = 1000 ' how often to "pop" the timer.
TimerID = SetTimer(0&, 0&, TimerSeconds * 1000&, AddressOf TimerProc)
End Sub
Sub EndTimer()
On Error Resume Next
KillTimer(0&, TimerID)
End Sub
Sub TimerProc(ByVal HWnd As Long, ByVal uMsg As Long,
ByVal nIDEvent As Long, ByVal dwTimer As Long)
MsgBox("test123")
End Sub

Answer 1

It appears that your PInvoke signature is wrong. Try this one instead:
Public Delegate Sub TimerProc(ByVal hWnd As IntPtr, ByVal uMsg As UInteger, ByVal nIDEvent As IntPtr, ByVal dwTime As UInteger)
<DllImport("user32.dll", SetLastError:=True)> _
Public Shared Function SetTimer(ByVal hWnd As IntPtr, ByVal nIDEvent As IntPtr, ByVal uElapse As UInteger, ByVal lpTimerFunc As TimerProc) As IntPtr
End Function
You will need to change your pinvoke signature for KillTimer as well. See pinvoke.net for more information.

Answer 2

I got it to work with this:
Imports System.Runtime.InteropServices
Public Class TimerMethods
<DllImport("user32.dll", SetLastError:=True)>
Public Shared Function SetTimer(ByVal hWnd As IntPtr, ByVal nIDEvent As IntPtr, ByVal uElapse As UInteger, ByVal lpTimerFunc As TimerProc) As IntPtr
End Function
<DllImport("user32.dll", SetLastError:=True)>
Public Shared Function KillTimer(ByVal hWnd As IntPtr, ByVal nIDEvent As IntPtr) As Boolean
End Function
Public Delegate Sub TimerProc(ByVal hWnd As IntPtr, ByVal uMsg As UInteger, ByVal nIDEvent As IntPtr, ByVal dwTime As UInteger)
Public timerID As IntPtr
Sub StartTimer(windowHandle As IntPtr)
Dim timerSeconds = 3 ' how often to "pop" the timer.
timerID = SetTimer(windowHandle, IntPtr.Zero, CUInt(timerSeconds * 1000), AddressOf TimerMethods.TimerCallback)
If timerID = IntPtr.Zero Then
Debug.WriteLine("Timer start error.")
Else
Debug.WriteLine("Timer started.")
End If
End Sub
Sub EndTimer()
KillTimer(IntPtr.Zero, timerID)
End Sub
Public Shared Sub TimerCallback(ByVal hWnd As IntPtr, ByVal uMsg As UInteger, ByVal nIDEvent As IntPtr, ByVal dwTime As UInteger)
MsgBox(uMsg)
End Sub
End Class
and a simple form with just a button on it to start the timer:
Public Class Form1
Dim t As TimerMethods
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
t = New TimerMethods
t.StartTimer(Me.Handle)
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
If t IsNot Nothing Then
t.EndTimer()
End If
End Sub
End Class
You don't have to use windowHandle to tie the timer to the form: you could use IntPtr.Zero instead.
Any time you see a variable name like hWnd, it wants a handle, which is an IntPtr in VB.NET.
Reference: pinvoke.net/default.aspx/user32.SetTimer

Answer 3

There seems little point in using PInvoke to do this. There is a Windows Forms Timer that you can use easily:
Public Class Form3
Private _timer As Timer
Public Sub StartTimer()
_timer = New Timer()
_timer.Interval = 1000 ' timer interval in ms
AddHandler _timer.Tick, AddressOf TimerProc
_timer.Enabled = True
End Sub
Public Sub EndTimer()
_timer.Enabled = False
RemoveHandler _timer.Tick, AddressOf TimerProc
End Sub
Sub TimerProc(sender As Object, e As EventArgs)
MsgBox("test123")
End Sub
End Class

Answer 4

I have tested the code in VBE in Excel 2013 and run successfully.

Answer 5

I state beforehand that this solution is for VBA environment
since that was a possible one at the stage I wrote it
I made it run with some edits:
added the continuation escape sequence "_" at the end of each but the last line of SetTimer() and KillTimer () function declaration
in EndTimer() assigned KillTimer to a Long variable, which I also declared
in TimerProc() added a call to EndTimer() to stop it !!!
here follows the working code for me:
Option Explicit
Public Declare Function SetTimer Lib "user32" ( _
ByVal HWnd As Long, _
ByVal nIDEvent As Long, _
ByVal uElapse As Long, _
ByVal lpTimerFunc As Long) As Long
Public Declare Function KillTimer Lib "user32" ( _
ByVal HWnd As Long, _
ByVal nIDEvent As Long) As Long
Public TimerID As Long
Public TimerSeconds As Single
Sub StartTimer()
TimerSeconds = 1000 ' how often to "pop" the timer.
TimerID = SetTimer(0&, 0&, TimerSeconds * 1000&, AddressOf TimerProc)
End Sub
Sub EndTimer()
Dim i As Long '<--| added
On Error Resume Next
i = KillTimer(0&, TimerID) '<--| added
End Sub
Sub TimerProc(ByVal HWnd As Long, ByVal uMsg As Long, _
ByVal nIDEvent As Long, ByVal dwTimer As Long)
MsgBox ("test123")
EndTimer '<--| added !!!
End Sub