Control Usage

Make a Property Page

1. Create a new ActiveX control project. Give the control properties.
2. Invoke the Project menu's Add Property Page command. It is set to a standard size so don't resize it.
3. On the property page:
   1. Add controls to let the user view and modify the properties.
   2. Create Boolean variables to indicate when the user changes each value.
   3. In the PropertyPage_SelectionChanged event handler, set the values of the controls on the property page using the property values from the selected controls in the application. Set the property Booleans to False and set Changed to False.
   4. When the user changes a property value, set its Boolean to True and set Changed to True.
   5. In the PropertyPage_ApplyChanges event handler, see which properties have been changed and set those values for the selected controls.
4. Connect the property page:
   1. Open the control's form window.
   2. In the Properties window, click on the Property Pages entry. Then double click the ellipsis (...) to the right.
   3. Check the box next to your property page and click Ok.

Click here to download an example program.

The traditional combo box on typing a character doesn't lists the matching values in the combo box. For this purpose we can use Microsoft Forms 2.0 Library under references. This combo box is a very good one where in on typing a single character the first matching value is selected and on selecting the second the next closer matching value is displayed and so on.

Microsoft does not recommend the usage of this library. It differs from Office version to version, language to language. As a result, the installation process can damage office applications. This is an experimental knowledge and not accepted by Microsoft.

1. Create the dialogs form.
2. Create a ShowAbout subroutine in the control that displays the dialog.
3. Select the control's project in the Project Group window and open the Tools menu's Procedure Attributes command.
   1. In the Name combo box, select ShowAbout.
   2. Click the Advanced button.
   3. In the Procedure ID box, select "About Box."
   4. Click the Ok button.

My book Custom Controls Library shows how to do a lot of other ActiveX control stuff and includes the complete source code for 101 ready-to-run ActiveX controls.

To use the media player (in Windows NT) one have to be sure that the avi has at least 5 seconds of frames or some flicker and black frames will appear on screen. The media player has also some strange behaviors about what should be shown or not. One must make sure that if the controls are not visible, then the control itself must be visible. To make the control "disapear" just change the top to out of the screen image. Otherwise some phantom controls and sliders will surface somewhere on the screen.

After editting a control, re-OCXing it, loading the project and an error occurs do this:

1. Load the whole project
2. Say "yes" and "ok" to the messages that refer to continuing to load process
3. Second-Click on the side tool-bar and re-load you upgraded control.
4. Click Open from the file menu
5. When it asks you to save your project, ONLY save the .vbp files, ONLY!
6. When it asks you to load, re-load you project and your control should be upgraded!!!

Daniel wanted to load Web pages with the Web Browser control without loading pictures. With a little digging, he found that whether the pictures are loaded is controlled by the registry setting (all on one line):

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\
    AdvancedOptions\MULTIMEDIA\PICTS

When you change versions of a control, particularly ActiveX controls you are building, old projects may be unable to corrcetly load the control. When you load the project, Visual Basic replaces the control with a PictureBox having the control's name.

You can delete the PictureBoxes and replace them with new controls. If you have a lot of controls, that is a hassle.

Another solution is to open the project in a text editor and correct the control's version number. If the program does not use any features no longer supported by the control, it should work.

I found that populating the MSHFlexgrid control can be incredibly slow compared to populating the older MSFlexgrid control. If you do not need to use the hierarchical properties of the MSHFlexgrid then definitely use the MSFlexgrid..

In a recent application that I wrote to fill a large grid from a complex SQL call, I initially used the new MSHFlexgrid control and populated it for the user to view. The populating and updating of the grid took over 45 seconds. Just switching to the older MSFlexgrid control knocked down this to less than 15 seconds. This improvement made the wait just bearable!

[I have also noticed that you can speed the control up if you set Visible = False when you begin the update and then Visible = True when you are finished. The control doesn't actually go away in between, it just doesn't update every time you change a cell's value. -- Rod]

    ' Be careful using this option because if you
    ' have a code that says "Call Commad1_click"
    ' then it will not fire.
    Dim i As Integer

        For i = 0 To Form1.Controls.Count - 1
            Form1.Controls(i).Enabled = False
        Next i

To make the WebBrowser appear and look empty but normal, execute this code when the form loads:

    Private Sub Form_Load()
        wbrMainBrowser.Navigate "about:blank"
    End Sub

Give the control a meaningful name. If you call the control MyControl, then when the developer creates instances of the control, they will be named MyControl1, MyControl2, etc.

Give the control public properties and methods to let the developer control it. The ActiveX Control Interface Wizard can help with some of this.

Set the control's ToolboxBitmap property to the bitmap you want to display in the developer's toolbox. This bitmap should be 16 pixels wide and 15 tall. If it is not, Visual Basic will stretch it to fit. That usually produces an ugly result.

When you have given the control the properties and methods it needs, select the Project menu's Properties command at the bottom. Enter a meaningful project name and description on the General tab. On the Make tab, you can also enter the company name, copyright information, etc.

Now you are ready to build the OCX file. Select the File menu's Make Project_Name.ocx command. That's all there is to it.

To use the control, create a new Standard EXE project. Select the Project menu's Components command. In the dialog, find the new control. It will be listed using the description for the project that you entered in the project properties General tab.

When you click Ok, you should see the control's bitmap in the toolbar. You can now use the control just like any other.

There is a LOT more to say about ActiveX controls. For more information, look in my book Custom Controls Library. In addition to giving more information on control creation in general, this book shows how to build 101 useful custom controls. Complete source code is included on the CD-ROM. For more information including readers' comments and a table of contents, click here.

    Dim i As Integer

        For i = 0 To List1.ListCount - 1
            If List1.Selected(i) Then
                MsgBox List1.List(i) & " is selected."
            End If
        Next I

    Private Sub Text1_GotFocus()
        SendKeys "{home}+{end}"
    End Sub

    Private Sub Text1_GotFocus()
        Text1.SelStart = 0
        Text1.SelLength = Len(Text1.Text)
    End Sub

    CommonDialog1.Filter = _
        "Bitmap Files (*.bmp)|*.bmp|All Files (*.*)|*.*"

    Text1.SelStart = Len(Text1.Text)

    For i = Label1.LBound To Label1.UBound
        txt = txt & Label1(i).Caption & ", "
    Next i

    Private Sub Form_KeyPress(KeyAscii As Integer)
        If KeyAscii = 13 Then
            SendKeys "{TAB}"
            KeyAscii = 0
        End If
    End Sub