Vertical scrolling textbox (animated aboutbox)

• Download source code

Introduction

This article explains the usage and the source code of the usercontrol.

Background

Some years ago I needed a control been able to scroll text vertically. I needed this for an About-Form to present some credits. I found a basic solution by an author of an article named Paul Pickert on the page of planet-source-code.com. At present my requirements changed an I had to enhance the features of that basic solution.

Please be patient for language mistakes because English is not my native language.

Using the code

I like to divide the article into to parts. Part 1 explains the usage of the control by the developer. Part 2 the code structure and the basics behind.

Part 1: Control usage

The Properties setup:

Now you are ready to set the properties. In addition to the known properties of a usercontrol you may find two new properties Message and MessageTimer. They may also be found under the new category "extended properties" of the property page.

This two properties are representing two child controls of the user control. Message represents a label control and MessageTimer a standard timer control. Use the properties of this child controls and the main properties of the usercontrol to design your animatedTexbox control.

• Message.Text: holds the the scrolling text, lines may divided by vbCRlf
• Message.TextAlign: aligns the scrolling text
• MessageTimer.Interval: scrolling Interval in milliseconds. 50ms should be good.
• MessageTimer.Enabled: start/stop of scrolling

That's all!

Preparing the Windows Form that hosts the control:

Now we have to initialize the control when the parent form loads. We do this within the load event of the form, see code listing area.

Private Sub frmAbout_Load(sender As Object, e As EventArgs) Handles MyBase.Load
   ' define the text for the message. Use vbCrlf for carriage return/new line
   Dim strMessage As String = "Copyright fremde Programm Controls:" & vbCrLf
   strMessage = strMessage & "(Taken form codeproject.com)" & vbCrLf & vbCrLf
   strMessage = strMessage & "ImageView Control by Jordy Ruiter" & vbCrLf
   strMessage = strMessage & "MultiColCombobox by Gismo" & vbCrLf
   strMessage = strMessage & "CustValidatorTextbox by Vivek Bhatnagar" & vbCrLf
   ' ini the control property values
   animTextBox1.Message.Text = strMessage ' set the message text
   
    ' set no TextAlign to use the default center alignment
    ' set no timer interval to use the default value of 50 milliseconds
    animTextBox1.MessageTimer.Enabled = True 'start animation
End Sub 

Part 2: "The Controls Code"

1. Go and create an new project, choose Visual Basic as the language and type Windows Usercontrol.
2. Rename the usercontrol name and give it the name animTextbox. This name must be used, otherwise you will have a conflict using the helper classes for the toolbox icon (see description as follows).
3. Create 16x16 pixel bitmap (bmp) as the toolbox item bitmap and place file in the project folder. The name must be animToolbox.bmp.
4. Open the usercontrol in the designer.
5. Drag a panel control on it and set its Dock property to fill. Name it Panel1.
6. Drag a label control onto the panel control and set its position to the footer of the panel, name it labelMessage.
7. Open the code window of the usercontrol.

I divided the code into regions for better readability.

In the code header of the usercontrol we have to define the reference to import of the System.ComponentModel. We need this import for defining the extended usercontrol properties.

' ### neccessary Imports
Imports System.ComponentModel   

Next we have to define the code for the toolbox icon. This code is tied to the opening class statement. The code references two classes you have to attached to the usercontrols project. This helper classes are used to show the icon in the visual studio toolbox correctly. Please use them as the are. The content of the classes is not explained within this article because they are only helper classes.

 ' set the Toolbox Bitmap Icon 
 ' this done by the classes classToolboxIcon and clsTypeConverter
 <ToolboxItem(True)> <ToolboxBitmap(GetType(animTextBoxToolboxitem), "animTextBox.bmp")> _
Public Class animTextBox 

Next line under the opening class statement we define some global variables and for the animation we need a timer object.

 #Region "INI Variables, objects, events" ' ################ 
 ' ## Property variables 
 Private _Msg As Label = LabelMessage
 Private _TMR As Timer
 ' ## other variables
 Private intPosition = 0
 ' ## Private objects
 Private WithEvents objTimer1 As New Timer ' use withevents to get timer tick event
#End Region  

We will define the _Msg and _TMR variable as controls. This simple trick gives us the possibility to make the properties of this controls transparent through the usercontrol. Due to this the control user is able to modifiy the properties. If we will not do so the usercontrol only shows its own properties.

Now we can concentrate of defining some extra properties to enhance the standard properties of the usercontrol:

 #Region "extended usercontrol properties" ' ###########

' public all label object properties to be able to change them
<Browsable(True), Description("Textlabel of the message to hold the message text") _
, Category("extended Properties")> _
Public Property Message As Label
 Get
     Return LabelMessage
 End Get
 Set(value As Label)
     _Msg = value
 End Set
End Property

' public all timer object properties to be able to change them
<Browsable(True), Description("Timer for animation of the message") _
, Category("extended Properties")> _
Public Property MessageTimer As Timer
 Get
     Return objTimer1
 End Get
 Set(value As Timer)
     _TMR = value
 End Set
End Property
#End Region 

The first Property Message holds the usercontrol child control object labelMessage and the property MessageTimer the internal timer object.

The next step is defining the controls events:

In the load event we will populate the property variables _Msg and _TMR with the controls. At least we call the internal function ALignText() to make sure the scrolled text is aligned as requested..

 #Region "Control events" '#########################
' Event control loads
' set startup values
Private Sub animTextBox_Load(sender As Object, e As EventArgs) Handles Me.Load
 intPosition = Panel1.Height + 25 ' set initial start position
 _TMR = objTimer1 ' load property value with timer object
 _Msg = LabelMessage ' load property value with label object
 ' 50 (Milliseconds) should be a good timer.interval value for a smooth
 ' animation
 objTimer1.Interval = 50
 ALignText() ' reset text alignment
End Sub 

To managed the animation of the text we use the timer tick Event. To animate/scroll the text we start by setting the labelMessage.Top position outside (below) of the Panel1 control. Therefore it is not visible at the beginning.

Each timer tick we subtract 1 from the Top position value to force the labelMessage control to be redrawn 1 point higher to the top of the Panel1 control. This looks like an upward scrolling. We do so as long as the complete labelMessage Control is outside (above) the the Panel1 control. Therefore the labelMessage control is not visible.

If we reach this point we reset the position of the labelMessage control back to its start values. This mimics an endless scrolling text.

At least we call Application.DoEvents to release all pending application tasks that may be on hold during the timer tick task.

' Event timer tick = next animation step  
Private Sub objTimer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs)  _
Handles objTimer1.Tick 
 On Error Resume Next
 ' if there is no message text stop timer
 If LabelMessage.Text = "" Then
     objTimer1.Enabled = False
 Else
     ' increase/scroll label top point
     intPosition = intPosition - 1
     ' check if label is completly scrolled
     ' if yes reset label top position below panel to restart animation
     If intPosition = (LabelMessage.Height + 25) * -1 Then
         LabelMessage.Top = Me.Height + 25
         intPosition = LabelMessage.Top
     End If
     ' show label at new postion
     LabelMessage.Top = intPosition
 End If
 ALignText() ' make shure text alignment
 Application.DoEvents() ' give other app tasks a chance to work
End Sub 

To give the user of the application a chance to stop the scrolling may be for reading the static text we offer him the possibility do do so by pointing with the mouse cursor on the usercontrol area. To define this we use the Mouse.Enter and Mouse. leave events of the Panel1 control. ' Event cursor is entering/inside panel/control area

' stop the animation and set text to top 
Private Sub Panel1_MouseEnter(sender As Object, e As EventArgs) Handles Panel1.MouseEnter
     ' stop the timer and set the label.top position to the top of the panel
     objTimer1.Enabled = False
     LabelMessage.Top = Me.Height - 50
     ALignText()
End Sub

' Event cursor is leaving panel/control area
' restart the animation
Private Sub Panel1_MouseLeave(sender As Object, e As EventArgs) Handles Panel1.MouseLeave
 ' reset the label.top position below the panel to restart animation
 LabelMessage.Top = Me.Height + 25
 intPosition = LabelMessage.Top
 objTimer1.Enabled = True
End Sub  
#End Region 

Uff, we are coming to the rest of all that work. We have to define the function AlignText(). This will put the labelMessage Control to the left Border of the Panel1 control (left align) or it will center it.

  #Region "Private Functions/Subs" '#################
     ' Align the Textposition
     Sub ALignText()
         On Error Resume Next
         ' if the TextAlign property of the text label is set to left
         ' put the text label control to the left border of its parent (panel)
         If LabelMessage.TextAlign = ContentAlignment.TopLeft Then
             LabelMessage.Left = 1
         Else ' if not always center the text label (panel dock property is set to fill)
             Dim intW As Integer = Int(Me.Width / 2)
             Dim intW1 As Integer = Int(LabelMessage.Width / 2)
             Dim intDiff = intW - intW1
             If intDiff < 0 Then intDiff = 0 ' avoid negativ values
             LabelMessage.Left = intDiff
         End If
     End Sub 
 #End Region 
 end class

You are ready! Compile the project and use the created (animTextbox Control) DLL in your next projects.

To download a ZIP File with the Visual Studio Project use this Link: Download VerticalText.zip

Points of Interest

I traveled around in the internet an I found some solutions. In most cases they draw the text by using GDI functionality. I tried them and had the known flickering problem. Than I remembered the solution of Paul Pickert I found years ago which is a very simple Idea. At the end I learned that sometimes the simple solutions are the best way to go.

History

No updates yet because this is the initial version. If you may find bugs or have an idea to make things better please feel free to comment.