How To Create a Form That Always Stays on Top

Summary

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.

More Information

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.

Step-by-Step Example

  1. Start a new Standard EXE project. Form1 is created by default.
  2. Add two command buttons (Command1 and Command2) to Form1.
  3. Set the caption property of Command1 to "Always on top."
  4. Set the caption property of Command2 to "Normal."
  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

  6. On the Project menu, click Add Module, to add a new module to the project.
  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.


  8. Press F5 to run the project.
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).

References

For additional information, please see the following articles in the Microsoft Knowledge Base:

84251 How to Create a Topmost or Floating Window in Visual Basic


150233 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.
Propiedades

Id. de artículo: 184297 - Última revisión: 07/15/2004 - Revisión: 1

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