Hello,

I am programming a software which can be hidden with the starting parameter
/hide, e.g. program.exe /hide.

I then call  App.TaskVisible = False  which hides the program from the
taskbar.

This of course means, there is no way to get to the program again.

Now, the user should be able to run a program.exe /show, which makes the
program visible again. I do not want a second instance.

How do I make the original Program show up again?

regards,
Gunter

What you need is a method of communicating between applications

Option Explicit

' 29/07/2001  J French ISS Ltd
'
' Demonstration of communication between Apps
'
' Method: Send data from one App to Textbox
'         in another App
'
' Inspired by: Norstrom - developing Chat System
'
' Add 1 Commandbutton : cmdSend
'     1 Textbox       : txtSend
'     1 Textbox       : txtTarget
'
' NOTE:
'    txtTarget - MUST contain 'txtTarget' at design time
'
' Compile and run
'
' THIS DEMO ONLY WORKS WHEN THE APP IS COMPILED
'
' You can modify it to run
'    (slightly differently) in the IDE

Private Declare Function SendMessageStr _
        Lib "user32" _
        Alias "SendMessageA" _
        (ByVal hwnd As Long, _
         ByVal wMsg As Long, _
         ByVal wParam As Long, _
         ByVal S As String) _
        As Long

Private Declare Function FindWindowEx _
        Lib "user32" _
        Alias "FindWindowExA" _
        (ByVal hWnd1 As Long, _
         ByVal hWnd2 As Long, _
         ByVal lpsz1 As String, _
         ByVal lpsz2 As String) _
        As Long

Private Declare Function GetClassName _
        Lib "user32" _
        Alias "GetClassNameA" _
        (ByVal hwnd As Long, _
         ByVal lpClassName As String, _
         ByVal nMaxCount As Long) _
        As Long

Private Declare Function GetWindowText _
        Lib "user32" _
        Alias "GetWindowTextA" _
        (ByVal hwnd As Long, _
         ByVal lpString As String, _
         ByVal cch As Long) As Long

Private Const WM_SETTEXT = &HC

Private hTgt&

Private Sub Form_Load()
    Dim S$

    Me.Top = 0
    Me.AutoRedraw = True
    Me.Caption = "TARGET"
    cmdSend.Enabled = False
    txtSend.Enabled = False

    If App.PrevInstance Then
       Me.Caption = "SOURCE"
       Call LS_FindTarget
       cmdSend.Enabled = True
       txtSend.Enabled = True
       txtTarget.Enabled = False
       Me.Left = Screen.Width - Me.Width
    End If

    If App.PrevInstance = 0 Then
       Me.Left = 0
       S$ = App.Path
       If Right$(S$, 1) <> "\" Then
          S$ = S$ + "\"
       End If
       Shell S$ + App.EXEName, vbNormalFocus
    End If
End Sub

Private Sub cmdSend_Click()
    Static Count&
    Count = Count + 1
    LS_Send "Msg" + Str$(Count) + ":" + txtSend.Text
End Sub

' --- Locate TARGET App and Textbox
Private Sub LS_FindTarget()
    Dim hApp&

    ' --- locate Top Window with Caption "TARGET"
    hApp = FindWindowEx(0, 0, vbNullString, "TARGET")
    Me.Print "hApp:"; hApp
    Me.Print LF_ClassName(hApp); " / "; LF_WindowText(hApp)
    ' --- locate the Textbox containing 'txtTarget' at design time
    hTgt = FindWindowEx(hApp, 0, vbNullString, "txtTarget")
    Me.Print "hTgt:"; hTgt; " / "; LF_WindowText(hTgt)
    Me.Print LF_ClassName(hTgt)
End Sub

' --- actually push data to the TARGET instance
Private Sub LS_Send(S$)
    Call SendMessageStr(hTgt, WM_SETTEXT, 0, S$)
End Sub

' --- prove that we activate the TARGET App
Private Sub txtTarget_Change()
    If Me.CurrentY > Me.ScaleHeight - 250 Then Me.Cls
    Me.Print txtTarget.Text
End Sub

Private Function LF_ClassName(Hnd&) As String
    Dim Q&, S$
    S$ = Space$(100)
    ' ---
    Q = GetClassName(Hnd, S$, Len(S$))
    LF_ClassName = Left$(S$, Q)
End Function

Private Function LF_WindowText(Hnd&) As String
    Dim Q&, S$
    S$ = Space$(100)
    ' ---
    Q = GetWindowText(Hnd, S$, Len(S$))
    LF_WindowText = Left$(S$, Q)
End Function

On Fri, 29 Mar 2002 02:09:21 +0100, "Gunter Schmidt"