Microsoft Visual Basic does not offer a property or method to make a form
the topmost window. This behavior can be achieved using the SetWindowPos
Win32 API.
This article demonstrates how to set a form as the topmost window using the
SetWindowPos Win32 API.
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The sample code below uses a function called SetTopMostWindow. The
SetTopMostWindow function sets a window as a topmost Window or as a normal
Window, based on the two parameters, hwnd and Topmost, passed to it.
The hwnd parameter specifies the handle of the window to be set as topmost
or as normal.
The Topmost parameter specifies whether to set the form as topmost or as
normal. If the value is true, the function sets the form to always remain
on top. If the value is false, the function sets the form as a normal
window.
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Step-by-Step Example
| 1. | Start a new Standard EXE project. Form1 is created by default.
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| 2. | Add two command buttons (Command1 and Command2) to Form1.
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| 3. | Set the caption property of Command1 to "Always on top."
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| 4. | Set the caption property of Command2 to "Normal."
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| 5. | Put the following code in the Form1 Declaration section:
Option Explicit
Private Sub Command1_Click()
Dim lR As Long
lR = SetTopMostWindow(Form1.hwnd, True)
End Sub
Private Sub Command2_Click()
Dim lR As Long
lR = SetTopMostWindow(Form1.hwnd, False)
End Sub
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| 6. | On the Project menu, click Add Module, to add a new module to the
project.
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| 7. | Add the following code to the new module:
Option Explicit
Public Const SWP_NOMOVE = 2
Public Const SWP_NOSIZE = 1
Public Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
Public Const HWND_TOPMOST = -1
Public Const HWND_NOTOPMOST = -2
Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" _
(ByVal hwnd As Long, _
ByVal hWndInsertAfter As Long, _
ByVal x As Long, _
ByVal y As Long, _
ByVal cx As Long, _
ByVal cy As Long, _
ByVal wFlags As Long ) As Long
Public Function SetTopMostWindow(hwnd As Long, Topmost As Boolean) _
As Long
If Topmost = True Then 'Make the window topmost
SetTopMostWindow = SetWindowPos(hwnd, HWND_TOPMOST, 0, 0, 0, _
0, FLAGS)
Else
SetTopMostWindow = SetWindowPos(hwnd, HWND_NOTOPMOST, 0, 0, _
0, 0,FLAGS)
SetTopMostWindow = False
End If
End Function
NOTE: In the above sample code, an underscore (_) at the end of a line is
used as a line-continuation character.
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| 8. | Press F5 to run the project.
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If you click the "Always on top" command button, your form becomes the
topmost window and remains on top of every window; you cannot move any
other window on top of it. If you click the "Normal" button, the form
behaves normally (you can move other windows on top of it).
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For additional information, please see the following articles in the
Microsoft Knowledge Base:
84251 (http://support.microsoft.com/kb/84251/EN-US/)
How to Create a Topmost or Floating Window in Visual Basic
150233 (http://support.microsoft.com/kb/150233/EN-US/)
BUG: Topmost Window Does Not Stay on Top in Design Environment
Also view the sample project, CallDlls, located in the VB\Samples\CallDlls
folder. The CallDlls sample has code to set a Form as the topmost window
and is illustrated in the sample.
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