Make Your Own Control - Part 1

Tuesday Nov 19th 2002 by Sam Huggill
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Make your own control: Part 1

Ever wondered how to put all of your 500-line code into your own control? Well now there's a way.

Using the Visual Basic 5 Control Creation Edition or Visual Basic 5 (although the CCE is free), you can create your own controls. This has been very beneficial to companies such as Data-Dynamics and Sheridan. They have made a lot of money with their own controls (see my previous article on custom controls).

Well, in the next two weeks I will show you a simple demonstration of how to make two different types of controls.

The first will make your program stay 'on top'. Make a new ActiveX control and add a .bas module (Project, Add Module). This first piece of code sets some constants and uses an API call on the 'user32' library. Add this code to the module:

Public Const HWND_TOPMOST = -1 
Public Const HWND_NOTOPMOST = -2 
Public Const SWP_NOMOVE = &H2 
Public Const SWP_NOSIZE = &H1 
Public Const SWP_NOACTIVATE = &H10 
Public Const SWP_SHOWWINDOW = &H40 
Public Const TOPMOST_FLAGS = SWP_NOMOVE Or SWP_NOSIZE  

  Public Declare Function SetWindowPos Lib "user32"
(ByVal hwnd As Long,
ByVal hWndInsertAfter As Long, ByVal x As Long, y, _
ByVal cx As Long, ByVal cy As Long,
ByVal wFlags As Long) As Long

Now that the raw material is in place, you can set some properties for the control.

By default, the control name is 'UserControl1'. Change its name to something relevant like 'OnTop'. Change the CanGetFocus property to False and the InvisibleAtRunTime property to True. Give it a nice picture and leave the ToolboxBitmap property to None, unless you feel the desire to give it a meaningless picture!

Open up the code window for the Control, and go to the General Declarations procedure. This code adds a method statement, which makes the program 'normal':

Public Sub MakeNormal(Handle As Long)  

  SetWindowPos Handle, HWND_NOTOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS  

End Sub  

Now add this method statement to put the program on top:

Public Sub MakeTopMost(Handle As Long)  

  SetWindowPos Handle, HWND_TOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS  

End Sub  

Right, time to compile the control. Click File, Make OnTop.ocx. Now save the project (File, Save Project).

Click File, New Project. Select a Standard EXE file. Click Project, Components. Click on the Browse button. Go to the directory where you made the OCX file and double click on it. Click OK. Draw the control on to the form. Open up the code window for the form. Go to the form's Load procedure. Add this code:

Private Sub Form_Load() 
  OnTop1.MakeTopMost (Me.hwnd) 
End Sub

Or, if you want it to become normal, use:

Private Sub Form_Load() 
  OnTop1.MakeNormal (Me.hwnd) 
End Sub

Run the Project (F5).

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